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1.
A phylogenetic analysis was performed for 34 Aspergillus strains belonging to section Nigri. Molecular methods allowed for the correct classification into three different clades ( A. niger, A. tubingensis, and A. foetidus). Correlation with in vitro itraconazole susceptibility distinguished the following three profiles: susceptible, resistant, and showing a paradoxical effect. A number of different species whose morphological features resemble those of A. niger showed unusual MICs to itraconazole that have never been described for the Aspergillus genus.Black aspergilli are widely distributed in nature ( 16); they are common food spoilers but are also well used for industrial purposes ( 15). Among Aspergillus species of the Nigri group, A. niger constitutes the most frequent etiological agent of otomycosis ( 13) and is considered the third cause of pulmonary aspergillosis ( 10). Nevertheless, the clinical implications of other species are rarely reported, and they are generally identified as A. niger ( 14, 22).Clinically, identification of unknown Aspergillus clinical isolates to the species level may be important given that different species have dissimilar susceptibilities to antifungal drugs. Thus, the knowledge of the species identity may influence the choice of appropriate antifungal therapy ( 2, 4). Furthermore, since the antifungal susceptibility patterns for most of the species within section Nigri have been poorly investigated, their identification and antifungal susceptibility profiles appear to be of clinical interest for further research.Black aspergilli belong to one of the most difficult groups concerning classification and identification ( 18), and so a number of different techniques have been developed in order to solve this issue. Among them, molecular tools are the gold standard ( 1, 18), as the sequencing of the β-tubulin or calmodulin gene is suitable, and enough, to discriminate between species within section Nigri ( 3, 18, 21).Thirty-four Aspergillus section Nigri strains belonging to the Mold Collection of the Centro Nacional de Microbiologia and collected since 2004 were analyzed. Thirty-three strains were independent clinical isolates, and 1 had an environmental origin. All strains were identified as A. niger using conventional methods of morphology at the macroscopic as well as microscopic levels ( 9). Species identification analysis was addressed using sequences of the β-tubulin gene from all the strains included in this study together with the sequences of different Aspergillus section Nigri type strains and others that were available at GenBank as follows: A. tubingensis {"type":"entrez-nucleotide","attrs":{"text":"AY820007","term_id":"65307061","term_text":"AY820007"}}AY820007T, {"type":"entrez-nucleotide","attrs":{"text":"AY820009","term_id":"65307063","term_text":"AY820009"}}AY820009, and {"type":"entrez-nucleotide","attrs":{"text":"AY585527","term_id":"53830386","term_text":"AY585527"}}AY585527; A. foetidus {"type":"entrez-nucleotide","attrs":{"text":"AY585533","term_id":"53830397","term_text":"AY585533"}}AY585533T, {"type":"entrez-nucleotide","attrs":{"text":"AY585534","term_id":"53830399","term_text":"AY585534"}}AY585534, and {"type":"entrez-nucleotide","attrs":{"text":"DQ768454","term_id":"111609935","term_text":"DQ768454"}}DQ768454; and A. niger {"type":"entrez-nucleotide","attrs":{"text":"FJ629288","term_id":"225904264","term_text":"FJ629288"}}FJ629288T, {"type":"entrez-nucleotide","attrs":{"text":"EF422213","term_id":"126105445","term_text":"EF422213"}}EF422213, and {"type":"entrez-nucleotide","attrs":{"text":"AY585537","term_id":"53830403","term_text":"AY585537"}}AY585537. Partial sequences of the β-tubulin gene were amplified using the primer set βtubAniger1 and βtubANiger2 ( 11) and were carried out according to standard PCR guidelines (Applied Biosystems). Sequences were assembled and edited using the SeqMan II and EditSeq software packages (Lasergene 8.0; DNAStar, Inc., Madison, WI).All phylogenetic analyses were conducted with InfoQuest FP software, version 4.50 (Bio-Rad). The methodology used was maximum parsimony clustering. Phylogram stability was assessed by using parsimony bootstrapping with 2,000 simulations and by using the Aspergillus clavatus {"type":"entrez-nucleotide","attrs":{"text":"AY214441","term_id":"32441964","term_text":"AY214441"}}AY214441T sequence as the out-group.The phylogenetic tree grouped the 34 clinical isolates into three different clades consisting of 13 A. niger isolates, 18 A. tubingensis isolates, and 3 A. foetidus isolates (Fig. ). Table shows β-tubulin gene identification, as well as the origin and susceptibility profiles of the isolates. Open in a separate windowPhylogenetic tree using maximum parsimony phylogenetic analysis and 2,000 bootstrap simulations based on β-tubulin gene sequences from all the Aspergillus section Nigri strains included in the study. Percentages indicate the bootstrap support for each group of sequences. (T), type strain. TABLE 1.Source, molecular identification, MICs, and MECs for species of Aspergillus section NigriaIsolate | Source | Molecular identification (β-tubulin gene) | MIC (mg/liter)b
| MEC (mg/liter)c
|
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AMB | ITC | VCZ | RVC | POS | TRB | CAS | MICA |
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Isolates of Aspergillus section Nigri showing low ITC MICs | | | | | | | | | | | CM-3236 | Respiratory | A. niger | 0.19 | 0.5 | 0.5 | 1.0 | 0.12 | 1.0 | 0.25 | 0.03 | CM-3257 | Respiratory | A. niger | 0.25 | 1.0 | 1.0 | 1.0. | 0.25 | 1.0 | 0.25 | 0.03 | CM-3506 | Respiratory | A. niger | 0.19 | 0.5 | 0.75 | 1.0 | 0.12 | 0.31 | 0.15 | 0.03 | CM-3507 | Respiratory | A. tubingensis | 0.19 | 0.5 | 1.0 | 1.5 | 0.15 | 0.62 | 0.06 | 0.03 | CM-3585 | Environmental | A. tubingensis | 0.19 | 0.5 | 1.0 | 1.67 | 0.12 | 0.42 | 0.37 | 0.03 | CM-3586 | Catheter | A. niger | 0.25 | 0.5 | 1.0 | 2.0 | 0.12 | 0.12 | 1.0 | 0.03 | CM-3636 | Respiratory | A. niger | 0.25 | 0.5 | 0.5 | 1.0 | 0.19 | 1.0 | 0.25 | 0.03 | CM-3641 | Respiratory | A. niger | 0.25 | 0.5 | 1.0 | 1.0 | 0.125 | 0.25 | 0.5 | 0.03 | CM-3672 | Cutaneous | A. niger | 0.12 | 0.5 | 1.0 | 1.5 | 0.19 | 0.07 | 0.15 | 0.03 | CM-4004 | Unknown | A. niger | 0.25 | 1.0 | 1.0 | 1.67 | 0.25 | 0.13 | 0.10 | 0.03 | CM-4213 | Respiratory | A. niger | 0.33 | 0.14 | 0.33 | 0.58 | 0.03 | 0.22 | 0.39 | 0.03 | CM-4264 | Blood culture | A. tubingensis | 0.12 | 0.5 | 1.0 | 1.5 | 0.12 | 0.50 | 0.03 | 0.03 | CM-4296 | Respiratory | A. tubingensis | 0.12 | 0.75 | 1.0 | 1.5 | 0.19 | 0.62 | 0.25 | 0.03 | CM-4316 | Respiratory | A. niger | 0.19 | 0.5 | 0.5 | 1.0 | 0.125 | 0.5 | 0.25 | 0.03 | CM-5094 | Respiratory | A. tubingensis | 0.12 | 0.5 | 0.75 | 2.0 | 0.06 | 0.62 | 0.19 | 0.03 | CM-5095 | Respiratory | A. niger | 0.19 | 0.5 | 0.75 | 1.5 | 0.12 | 0.62 | 0.25 | 0.03 | GM for group | | | 0.20 | 0.56 | 0.82 | 1.31 | 0.14 | 0.50 | 0.28 | 0.03 | Isolates of Aspergillus section Nigri showing much higher ITC MICs | | | | | | | | | | | CM-3123 | Respiratory | A. tubingensis | 0.25 | 11 | 1.67 | 2.67 | 0.25 | 1.17 | 0.25 | 0.03 | CM-3810 | Respiratory | A. tubingensis | 0.25 | 4.0 | 2.0 | 2.0 | 0.12 | 1.0 | 0.5 | 0.03 | CM-4003 | Unknown | A. tubingensis | 0.12 | 16 | 2.0 | 4.0 | 0.25 | 1.0 | 0.25 | 0.03 | CM-4005 | Unknown | A. tubingensis | 0.12 | 16 | 2.0 | 4.0 | 0.5 | 0.25 | 0.5 | 0.03 | CM-4688 | Respiratory | A. tubingensis | 0.21 | 3.67 | 2.0 | 3.33 | 0.25 | 1.50 | 0.18 | 0.03 | CM-5264 | Respiratory | A. foetidus | 0.12 | 16 | 2.0 | 8.0 | 0.5 | 0.5 | 0.06 | 0.03 | GM for group | | | 0.18 | 11.11 | 1.95 | 4.0 | 0.31 | 0.90 | 0.29 | 0.03 | Isolates of Aspergillus section Nigri showing paradoxical effect against ITC | | | | | | | | | | | CM-3125 | Respiratory | A. tubingensis | 0.12 | 0.5 | 1 | 1.67 | 0.12 | 0.5 | 0.05 | 0.03 | CM-3177 | Respiratory | A. tubingensis | 0.16 | 1 | 2 | 3.33 | 0.25 | 0.67 | 0.05 | 0.03 | CM-3551 | Respiratory | A. niger | 0.5 | 4.75 | 1 | 2 | 0.12 | 0.25 | 0.03 | 0.03 | CM-3654 | Blood culture | A. tubingensis | 0.19 | 1 | 2 | 2.50 | 0.25 | 0.63 | 0.14 | 0.03 | CM-4000 | Unknown | A. tubingensis | 0.16 | 1 | 2 | 2 | 0.25 | 0.33 | 0.10 | 0.03 | CM-4001 | Unknown | A. tubingensis | 0.19 | 1 | 1.75 | 2.50 | 0.25 | 0.56 | 0.11 | 0.03 | CM-4002 | Unknown | A. foetidus | 0.25 | 1 | 2 | 2.67 | 0.12 | 0.33 | 0.14 | 0.03 | CM-4262 | Ophthalmic | A. niger | 0.25 | 1 | 2 | 2 | 0.25 | 0.29 | 0.13 | 0.03 | CM-4352 | Respiratory | A. tubingensis | 0.28 | 1 | 0.88 | 2 | 0.25 | 0.31 | 0.15 | 0.03 | CM-4897 | Blood culture | A. tubingensis | 0.16 | 1 | 2 | 2 | 0.25 | 0.42 | 0.10 | 0.03 | CM-4899 | Respiratory | A. tubingensis | 0.16 | 1 | 2 | 2.67 | 0.25 | 0.33 | 0.10 | 0.05 | CM-4995 | Prosthesis | A. foetidus | 0.21 | 1 | 2 | 2 | 0.16 | 0.33 | 0.14 | 0.03 | GM for group | | | 0.2 | 1.3 | 1.72 | 2.28 | 0.21 | 0.41 | 0.10 | 0.03 | Open in a separate windowaGM, geometric means of MICs and MECs for the strains within each group. bMIC geometric mean of amphotericin B (AMB), itraconazole (ITC), voriconazole (VCZ), ravuconazole (RVC), posaconazole (POS), and terbinafine (TRB). cMEC geometric mean of caspofungin (CAS) and micafungin (MICA).Antifungal susceptibility testing (AST) was performed following the EUCAST Definitive Document E.DEF 9.1 method for the determination of broth dilution MICs of antifungal agents for conidium-forming molds ( 17). Antifungal ranges used in the microdilution assays have been described previously ( 2). Endpoints were determined at 48 h. The endpoint for MEC determination was the minimal antifungal concentration that produced morphological alterations of hyphal growth at 48 h. The paradoxical effect to itraconazole was defined as an increase in growth occurring at least 2 drug dilutions above the MIC. AST was repeated at least twice on different days.Three different antifungal patterns were clearly distinguishable based on the itraconazole MIC values (Table ): low and high itraconazole MICs and a third group (12 strains) showing an uncommon paradoxical effect of this antifungal ( 5). Either those strains classified as paradoxical strains or those showing much higher itraconazole MICs also had higher MIC values to voriconazole and ravuconazole.Posaconazole showed better activity in vitro. Moreover, all strains were susceptible to the rest of the following antifungals tested: amphotericin B, terbinafine, and echinocandins.In summary, A. niger MICs for itraconazole, voriconazole, and ravuconazole were slightly higher than A. fumigatus MICs and even more so for A. tubingensis and A. foetidus MICs. Identification of clinical isolates belonging to Aspergillus section Nigri and involved in proven or probable infections should be to the species level because it is the only way to monitor the development of secondary resistances of these molds ( 7, 8).The paradoxical effect or “Eagle effect” ( 12) has been previously described for yeasts or A. fumigatus but always in relation to echinocandins ( 5, 6, 19, 20). This is the first report showing the paradoxical effect of azole drugs against Aspergillus spp. The link between the paradoxical effect against itraconazole and a molecular mechanism responsible for it is yet to be determined, as is the clinical impact of those findings. Therefore, further studies including experimental models of aspergillosis to address any in vitro/in vivo correlations are warranted. 相似文献
2.
Thirty-six patients were treated with pristinamycin for 46 different microbiological isolates between April 2007 and July 2009. Pathogens included 9 methicillin-resistant Staphylococcus aureus isolates, 13 methicillin-resistant coagulase negative staphylococci, and 9 vancomycin-resistant enterococci. Sites of infections included 12 osteomyelitis cases, 10 prosthetic joints, 4 other prostheses, and 1 epidural abscess. Five patients ceased treatment due to side effects. Ten patients were cured of their infections, and 21 patients had infections successfully suppressed.The management of Gram-positive infections is becoming increasingly difficult as multidrug-resistant bacteria become more prevalent ( http://www.health.vic.gov.au/__data/assets/pdf_file/0005/331727/vre-report.pdf). Many complex infections require prolonged antibiotic therapy. The current therapeutic options have limitations, such as emerging bacterial resistance, the need for intravenous access, side effects, and cost ( 10).Pristinamycin is an oral streptogramin antibiotic made up of two synergistic but structurally unrelated components, pristinamycin IA and pristinamycin IIA. Separately, each component has bacteriostatic activity. Together, they have bactericidal action ( 8). Pristinamycin has a wide range of in vitro activity, including against most Gram-positive cocci and Clostridium, Haemophilus, Neisseria, Chlamydia, and Ureaplasma species ( 1, 5, 6). Enterococcal species generally are less sensitive to pristinamycin than staphylococci or streptococci in vitro ( 6). This may be because enterococci are naturally resistant to streptogramin A ( 4). Most enterococci that also are resistant to streptogramin B remain sensitive to the combination of agents in pristinamycin ( 2, 6). There have been only limited reports of its use in the English-language literature ( 3, 7).This retrospective study was carried out at a single adult tertiary hospital in Australia. Pharmacy dispensing records were searched to identify all patients prescribed pristinamycin up to July 2009. One patient was excluded, as only two doses of pristinamycin were administered and no conclusions could be drawn. A single trained researcher viewed the medical records to collect information regarding patient management and outcome. Data were collected up to a predetermined study closure date of 1 September 2009. Cure was defined as no evidence of recurrence at follow-up after the cessation of antibiotics. Suppression was defined as improvement in imaging, inflammatory markers, and clinical condition while continuing antibiotic treatment. Failure was defined as either the lack of a clinical response to treatment or intolerance requiring the withdrawal of treatment. Where polymicrobial infection existed, the outcome was attributed to all organisms susceptible to pristinamycin. The dose and duration of pristinamycin therapy was at the discretion of the prescribing physician. There is no standardized testing method for pristinamycin susceptibility. Testing for in vitro susceptibility to quinupristin-dalfopristin by Vitek 2 was used as a proxy for pristinamycin susceptibility ( 7, 9). Other antibiotic susceptibilities were determined according to standard NCCLS criteria. Coagulase-negative staphylococci (CNS) were grouped together and classified as either methicillin-sensitive CNS or methicillin-resistant CNS based on in vitro susceptibility testing.Thirty-six patients were treated with pristinamycin for 46 microbiological isolates. Table details the patient characteristics. Bone and joint infection was the most common indication, with 12 patients having osteomyelitis and 10 having prosthetic joint infections. Other indications included one prosthetic mitral valve endocarditis, one permanent pacemaker infection, two prosthetic vascular graft infections, four postoperative wound infections, two intravenous-line-related bacteremias, two intraabdominal infections, one urinary tract infection, and one epidural abscess. Tables and show details of individual patients and outcomes stratified to patient demographics. TABLE 1.Patient demographics and comorbidities Demographic/comorbidity | No. |
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Total | 36 | Median age in yr (range) | 63.5 (33-91) | Diabetes mellitus | 15 (41.7%) | Chronic cardiac disease | 16 (44.4%) | Chronic respiratory disease | 11 (30.6%) | Chronic renal disease | 6 (16.7%) | Chronic liver disease | 4 (11.1%) | Malignancy | 3 (8.3%) | Immunosuppressive therapy | 9 (25%) | Open in a separate windowTABLE 2.Patient characteristics Study no. | Age (yr)/sexa | Conditionb | Organismc | Reason for use of pristinamycind | Dose | Antibiotic(s) prior to pristinamycin | Active concurrent antibiotic(s) | Duration of pristinamycin treatment (days) | Follow-up from commencement of pristinamycin (days) | Outcomed | Side effects, commentse |
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1 | 59/F | Intraabdominal collection | VRE-ns | R | 500 mg q8h | Teicoplanin (42 days) | | 35 | 174 | F/I | Nausea, vomiting | 2 | 81/M | Ascending cholangitis | VREF | R | 1 g q8h | | | 175 | 175 | S | | 3 | 53/F | Breast wound infection | MSSA | A | 1 g q8h | Clindamycin (1 dose), fusidic acid (2 doses), ciprofloxacin (39 days), rifampin (25 days) | Rifampin (35 days) | 35 | 35 | S | | 4 | 41/M | CVC infection, infected chronic venous thrumbosis | Resistant CNS | Short gut synd | 1 g q8h | Linezolid (28 days) | | 493 | 493 | S | | 5 | 53/M | Infected cephalic vein clots | Resistant CNS | R | 1 g q8h | Vancomycin (14 days) | | 13 | 82 | F/I | Neutropenia | 6 | 86/M | Epidural abscess | Presumed S. aureus | I | 1 g q12h | Rifampin and fusidic acid (28 days) | | 147 | 147 | S | | 7 | 33/M | Chronic osteomyelitis, femur | MRSA, VREF, sensitive CNS | R | 1 g q8h | Vancomycin (22 months), teicoplanin (42 days) | | 876 | 876 | S | Lethargy | 8 | 52/M | Osteomyelitis, ankle | MSSA, resistant CNS, Corynebacterium | R | 1 g q8h | Vancomycin (77 days) | | 208 | 208 | S | | 9 | 55/M | Osteomyelitis, foot | VRE-ns, sensitive CNS | R | 1 g q8h | Rifampin and fusidic acid (56 days) | | 76 | 429 | S | Nausea | 10 | 53/M | Osteomyelitis, foot | MRSA | I | 1 g q8h | Vancomycin (42 days) | | 192 | 192 | C | | 11 | 70/M | Osteomyelitis, ischial tuberosity | VREF | R | 1 g q8h | Linezolid (14 days) | | 32 | 489 | F/I | Diarrhea | 12 | 65/M | Osteomyelitis, mandible | MRSA | I | 1 g q8h | Vancomycin (14 days) | | 630 | 630 | S | | 13 | 62/M | Osteomyelitis, oleranon | MRSA | I | 1 g q8h | | | 399 | 399 | S | | 14 | 75/M | Osteomyelitis, sternal wound | Resistant CNS, Enterococcus faecalis | R | 1 g q8h | Vancomycin and timentin (13 days) | | 143 | 485 | C | | 15 | 55/M | Osteomyelitis, sternal wound | CNS resistant | I | 1 g q8h | Vancomycin (25 days), rifampin and fusidic acid (19 days) | | 101 | 127 | C | | 16 | 65/M | Osteomyelitis, sternal wound | MRSA | I | 500 mg q8h | Vancomycin (28 days), linezolid (28 days) | | 162 | 651 | C | Nausea | 17 | 83/M | Osteomyelitis, sternal wound | Resistant CNS, MSSA | R | 1 g q8h | Vancomycin (14 days) | | 19 | 19 | S | Death, suicide | 18 | 74/M | Osteomyelitis, sternal wound | MRSA, resistant CNS | R | 1 g q8h | Vancomycin (42 days) | | 121 | 121 | S | | 19 | 70/M | Sternal wound infection | Resistant CNS | R | 1 g q8h | Vancomycin (42 days) | | 120 | 511 | C | | 20 | 61/F | Sternal wound infection | MSSA | I, A, R | 1 g q8h | Vancomycin (28 days), rifampin and fusidic acid (13 days) | | 113 | 679 | C | | 21 | 91/F | Pace maker infection | Enterococcus faecium | R | 500 mg q8h | Vancomycin (7 days) | | 458 | 458 | S | | 22 | 71/F | Prosthetic hip joint infection, early | Resistant CNS | R | 1 g q8h | Vancomycin (28 days) | | 176 | 176 | S | | 23 | 75/F | Prosthetic hip joint infection, early | Resistant CNS | R | 1 g q8h | Rifampin and linezolid (28 days) | | 231 | 231 | S | | 24 | 73/M | Prosthetic hip joint infection, early | MRSA | I | 1 g q8h | Rifampin and fusidic acid (40 days) | | 399 | 399 | S | | 25 | 52/F | Prosthetic hip joint infection, early | VREF | R | 1 g q8h | Linezolid (28 days) | | 148 | 148 | S | Diarrhea, nausea | 26 | 74/F | Prosthetic hip joint infection, early | Resistant CNS, sensitive CNS | R | 1 g q8h | | Rifampin and ciprofloxacin (70 days) | 106 | 252 | C | Nausea | 27 | 56/M | Prosthetic knee joint and IM nail, early | MRSA | R | 1 g q8h | Rifampin and fusidic acid (7 days), Linezolid (7 days), Vancomycin (6 days) | | 94 | 94 | S | | 28 | 61/M | Prosthetic knee joint infection, early | Corynebacterium, Enterococcus faecalis | R | 1 g q8h | Vancomycin (42 days) | | 358 | 623 | C | | 29 | 58/M | Prosthetic knee joint infection, late | Resistant CNS | R | 1 g q8h | Vancomycin (42 days) | | 43 | 237 | F/I | Nausea, vomiting | 30 | 77/F | Prosthetic knee joint infection, early | Sensitive CNS | I | 1 g q8h | Rifampin and fusidic acid (13 days) | | 192 | 741 | C | Nausea, LOW, abnormal LFTs | 31 | 53/M | Prosthetic knee joint infection, early | Resistant CNS | R | 1 g q8h | Vancomycin (14 days) | | 338 | 338 | S | | 32 | 61/M | Prosthetic mitral valve endocarditis | VREF | R | 1 g q8h | Teicoplanin (84 days), linezolid (12 days) | | 12 | 124 | S | Death, gastrointestinal bleeding | 33 | 82/F | Prosthetic vascular graft infection | VREF | R | 500 mg q8h | Teicoplanin (42 days) | | 146 | 146 | S | | 34 | 73/F | Prosthetic vascular graft infection | VREF | R | 500 mg q8h | | | 65 | 65 | S | | 35 | 71/F | Total hip joint wound infection | MRSA | I | 1 g q8h | Vancomycin (14 days), rifampin and fusidic acid (12 days) | | 3 | 141 | F/I | Rash | 36 | 43/M | Urinary tract infection | Enterococcus faecium | R | 500 mg q8h | | | 8 | 196 | C | | Open in a separate windowaF, female; M, male. bCVC, central venous catheter; IM, intramedullary. cMRSA, methicillin resistant Staphylococcus aureus; MSSA, methicillin-sensitive Staphylococcus aureus; sensitive CNS, sensitive coagulase-negative staphylococci; resistant CNS, resistant coagulase-negative staphylococci; VREF, Vancomycin resistant Enterococcus faecium; VRE-ns, Vancomycin-resistant Enterococcus sp. not further speciated. dR, resistant; A, allergy; I, intolerance; C, cure; S, suppression; F, failure; short gut synd, concerns regarding absorption of rifampin. eLow, loss of weight; LFTs, liver function tests. TABLE 3.Outcome according to patient characteristics Treatment result | No. (%) of patients (n = 36) | Median age in yr (range) | Dose (no. of patients on regimen) | Median duration of treatment in days (range) | Median duration of follow-up in days (range) | No. of patients with each bacterial pathogenb | Site of infection |
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Cure | 10 (27.8) | 63 (43-77) | 1 g q8h (8), 500 mg q8h ( 2) | 131.5 (8-358) | 484.5 (127-741) | 2 MRSA, 1 MSSA, 2 sensitive CNS, 4 resistant CNS, 2 Enterococcus faecalis, 1 Enterococcus faecium, 1 Corynebacterium | 5 Osteomyelitis, 1 wound, 3 prosthetic joints, 1 urinary tract | Suppression | 21 (58.3) | 65 (33-91) | 1 g q8h (17), 500 mg q8h (3), 1 g 12 hourly (1) | 175 (12-876) | 208 (35-876) | 7 MRSA, 3 MSSA, 2 sensitive CNS, 7 resistant CNS, Enterococcus faecium 1, 7 VRE, 1 Corynebacterium | 6 Osteomyelitis, 2 wound, 1 prosthetic valve endocarditis, 6 prosthetic joints, 1 intravenous line, 2 vascular graft, 1 pace maker wire, 1 intraabdominal, 1 epidural abscess | Failurea | 5 (13.9) | 59 (53-71) | 1 g q8h (4), 500 mg q8h (1) | 32 (3-43) | 174 (82-489) | 1 MRSA, 2 resistant CNS, 2 VRE | 1 osteomyelitis, 1 wound,1 prosthetic joint, 1 venous thromboses, 1 intraabdominal collection | Open in a separate windowaAll failures were due to drug intolerance. bMRSA, methicillin resistant Staphylococcus aureus; MSSA, methicillin-sensitive Staphylococcus aureus; sensitive CNS, sensitive coagulase-negative staphylococci; resistant CNS, resistant coagulase-negative staphylococci; VRE, vancomycin-resistant enterococci.Bacterial pathogens treated included 9 cases of methicillin-sensitive Staphylococcus aureus, 4 of methicillin-resistant Staphylococcus aureus (MRSA), 4 of methicillin-sensitive CNS, 13 of methicillin-resistant CNS, 2 of Enterococcus faecalis, 2 of Enterococcus faecium, 9 of VRE (7 vancomycin-resistant Enterococcus faecium, 2 not speciated), and 2 of Corynebacterium species. Fifteen patients had mixed infections; eight of these had more than one pathogen treated with pristinamycin. In all cases, in vitro sensitivity to quinupristin-dalfopristin was demonstrated prior to prescribing pristinamycin.Twenty-four patients were prescribed pristinamycin due to resistance to alternative oral antibiotics, nine patients were intolerant of first-line antibiotics, two patients had allergic reactions to the first-line antibiotics, and one patient failed to absorb rifampin due to short-gut syndrome. The median duration of treatment was 144 days (range, 3 to 876 days), and the median follow-up was 223 days (range, 35 to 876 days). The most common dosing regimen was 1 g every 8 h (q8h). Thirty-two patients received other antibiotics before pristinamycin. Glycopeptide antibiotics were the most common of these.Ten patients were cured of infection, 21 had suppressed infection, and 5 patients failed treatment. The median time of follow-up after the cessation of antibiotic treatment in cured patients was 95 days (26 to 566). All failures were due to antibiotic intolerance. Two patients died while on treatment. Neither of these was related to the infection or the treatment with pristinamycin.Of the 11 patients reporting side effects, 6 experienced minor symptoms and continued treatment. Intolerant patients ceased therapy after a median of 31 days (2 to 42). Of these, three patients ceased treatment due to gastrointestinal side effects, one due to rash, and one due to neutropenia.Of the 10 patients treated for prosthetic joint infections, 3 were cured, 6 were successfully suppressed, and 1 patient failed therapy due to drug intolerance. Seven patients retained their prostheses. Pathogens treated in prosthetic joint infections were MRSA in two patients, methicillin-sensitive CNS in two patients, five cases of methicillin-resistant CNS, one case of vancomycin-sensitive E. faecalis, one case of VRE, and one case due to Corynebacterium (note that two patients had dual-pathogen infections).Nine patients with VRE infections were treated with pristinamycin. Of these, seven had clinically suppressed infections. Two patients failed treatment due to drug intolerance. Of the four patients treated with sensitive enterococcal infections, three were cured and one had suppressed infection.To date, only three studies describing the clinical utility of pristinamycin have been published in the English-language literature ( 3, 7, 9). Two describe the use of pristinamycin for osteoarticular infections ( 7, 9). One focuses on staphylococcal infections alone, with cure or suppression in 21 of 23 patients ( 7). This current study achieved cure or suppression in 21 of 22 patients with bone and joint infections. The second study reported cases of infection with several species of Gram-positive multidrug-resistant bacteria ( 9). In that study, five of six patients treated for VRE failed treatment. This contrasts with the current study, in which nine patients had VRE infection, and all patients who tolerated pristinamycin (seven out of nine) had a successfully suppressed infection at the time of study completion. This study adds important information about the potential role of pristinamycin in treating VRE infection.Given the prolonged therapy, the number of reported side effects was not surprising, but importantly the majority of these patients were able to continue treatment despite their symptoms. Patient numbers in this series are too small to comment on any factors associated with drug intolerance.This study has a number of limitations, including its retrospective nature and the inherent lack of controls. A further limitation is the fact many patients were treated with other antibiotics. It therefore is impossible to establish the relative impact of these antibiotics on patient outcomes.Our early pristinamycin experience has shown promising results, although larger series now are needed to explore issues such as drug tolerance and long-term outcomes. Pristinamycin appears to be a well-tolerated, effective oral alternative for treating difficult Gram-positive infections, including VRE and MRSA, in a number of difficult-to-treat or protected-site infections, including bone and joint infections and prosthetic device infections. 相似文献
3.
Agar dilution MIC methodology was used to compare the activity of sulopenem with those of amoxicillin/clavulanate, ampicillin/sulbactam, piperacillin-tazobactam, imipenem, clindamycin, and metronidazole against 431 anaerobes. Overall, MIC 50/ 90 values were as follows: sulopenem, 0.25/1.0 μg/ml; amoxicillin/clavulanate, 0.5/2.0 μg/ml; ampicillin/sulbactam, 0.5/4.0 μg/ml; piperacillin/tazobactam, 0.25/8.0 μg/ml; imipenem, 0.06/1.0 μg/ml; clindamycin, 0.25/16.0 μg/ml; and metronidazole, 1.0/4.0 μg/ml.Anaerobes are becoming increasingly resistant to β-lactams due to β-lactamase production and other mechanisms. Although β-lactamase production, and concomitant resistance to β-lactams, is the norm among the Bacteroides fragilis group, other anaerobic gram-negative bacilli in the genera Prevotella, Porphyromonas, and Fusobacterium have increasingly become β-lactamase positive. β-Lactamase production also has been described in clostridia. Metronidazole resistance in organisms other than non-spore-forming gram-positive bacilli has been described, as has clindamycin resistance in anaerobic gram-negative bacilli ( 1- 5).Although most anaerobes are susceptible to carbapenems, resistance has occurred. Quinolone resistance has developed, importantly in Clostridium difficile, necessitating development of other agents to treat pseudomembranous colitis ( 6, 8- 10, 12, 14, 16).CP-65,207, whose in vitro activity was published in 1989 ( 13), is a diastereomeric mixture of two isomers, the active component of the two being sulopenem. Sulopenem development was put on hold in the 1990s as discovery/development efforts were focused on gram-positive organisms. There is now an urgent need for drugs against gram-negative strains, and sulopenem has reentered clinical development (M. Huband, personal communication). PF-03709270 is a novel oral prodrug of sulopenem ( 11). The oral prodrug approach makes this compound unique among the penems and carbapenems. PF-03709270 and sulopenem both entered phase II studies in December 2008. The structures of sulopenem and its oral prodrug PF-03709270 are shown in Fig. and , respectively. Open in a separate windowChemical structure of sulopenem. Open in a separate windowChemical structure of PF-03709270, the oral prodrug of sulopenem.This study examined the activity of sulopenem compared with those of amoxicillin/clavulanate, ampicillin/sulbactam, piperacillin/tazobactam, imipenem, clindamycin, and metronidazole against 431 anaerobes.(This study was presented at the 48th Interscience Conference on Antimicrobial Agents and Chemotherapy, Washington, DC, 25 to 28 October 2008 [ 9a].)All anaerobes were clinical strains identified by standard procedures ( 16) and kept frozen in double-strength skim milk (dehydrated skim milk; BD, Sparks, MD) at −70°C until use. Prior to testing, strains were subcultured twice onto enriched brucella agar plates ( 7). Sulbactam and sulopenem susceptibility powders were obtained from Pfizer Central Research, Groton, CT, and other drugs were obtained from the respective manufacturers. β-Lactamase testing was performed by the nitrocefin disk method (Cefinase; BD, Sparks, MD). Agar dilution susceptibility testing was performed according to the latest method recommended by the Clinical and Laboratory Standards Institute (CLSI) ( 7), using brucella agar with 5% sterile laked sheep blood. Clavulanate and sulbactam were combined with amoxicillin and ampicillin, respectively, in 1:2 ratios, and tazobactam with piperacillin at a fixed concentration of 4.0 μg/ml. Breakpoint values, where CLSI approved, were as follows: amoxicillin/clavulanate, ≤4.0 μg/ml; ampicillin/sulbactam, ≤8.0 μg/ml; piperacillin/tazobactam, ≤32.0 μg/ml; imipenem, ≤4.0 μg/ml; clindamycin, ≤2.0 μg/ml; and metronidazole, ≤8.0 μg/ml. Quality control strains recommended by CLSI ( Bacteroides fragilis ATCC 25285, Bacteroides thetaiotaomicron ATCC 29741, and Eggerthella lenta ATCC 43055) were included with each run. Sulopenem MIC ranges for these strains were 0.06 to 0.125, 0.25, and 1.0 μg/ml, respectively.Among the anaerobic gram-negative bacilli tested, 95/101 (94%) of B. fragilis group strains, 57/100 (57%) of Prevotella/ Porphyromonas strains, and 3/60 (5%) of fusobacterial strains produced β-lactamase. Results of MIC testing are presented in Table . Overall, MIC 50/ 90 values were as follows: sulopenem, 0.25/1.0 μg/ml; amoxicillin/clavulanate, 0.5/2.0 μg/ml; ampicillin/sulbactam, 0.5/4.0 μg/ml; piperacillin/tazobactam, 0.25/8.0 μg/ml; imipenem, 0.06/1.0 μg/ml; clindamycin, 0.25/16.0 μg/ml; and metronidazole, 1.0/4.0 μg/ml. TABLE 1.MICs of the agents tested in this study Organism (no. of strains β-lactamase positive/no. tested) | Drug | MIC (μg/ml)a
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Range | 50% | 90% |
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Bacteroides fragilis (49/49) | Sulopenem | 0.03-2.0 | 0.125 | 0.5 | | Imipenem | 0.06-1.0 | 0.125 | 0.25 | | Amoxicillin/clavulanate | 0.25-4.0 | 0.5 | 2.0 | | Ampicillin/sulbactam | 0.5-8.0 | 1.0 | 8.0 | | Piperacillin/tazobactam | ≤0.125-4.0 | 0.5 | 2.0 | | Clindamycin | 0.03->32.0 | 1.0 | >32.0 | | Metronidazole | 0.25-2.0 | 1.0 | 1.0 | Bacteroides thetaiotaomicron (10/10) | Sulopenem | 0.25-0.5 | 0.25 | 0.5 | | Imipenem | 0.25 | 0.25 | 0.25 | | Amoxicillin/clavulanate | 0.5-8.0 | 1.0 | 4.0 | | Ampicillin/sulbactam | 1.0-8.0 | 2.0 | 8.0 | | Piperacillin/tazobactam | 4.0-16.0 | 8.0 | 16.0 | | Clindamycin | 1.0->32.0 | 4.0 | >32.0 | | Metronidazole | 1.0-2.0 | 1.0 | 2.0 | Bacteroides ovatus (10/10) | Sulopenem | 0.25-1.0 | 0.25 | 0.5 | | Imipenem | 0.125-0.5 | 0.125 | 0.25 | | Amoxicillin/clavulanate | 0.5-2.0 | 0.5 | 2.0 | | Ampicillin/sulbactam | 1.0-8.0 | 1.0 | 4.0 | | Piperacillin/tazobactam | 1.0-4.0 | 2.0 | 4.0 | | Clindamycin | 1.0->32.0 | 2.0 | >32.0 | | Metronidazole | 0.25-1.0 | 1.0 | 1.0 | Bacteroides vulgatus (10/10) | Sulopenem | 0.25-1.0 | 0.5 | 1.0 | | Imipenem | 0.25-1.0 | 0.5 | 0.5 | | Amoxicillin/clavulanate | 0.5-8.0 | 1.0 | 8.0 | | Ampicillin/sulbactam | 1.0-16.0 | 2.0 | 16.0 | | Piperacillin/tazobactam | 1.0-16.0 | 2.0 | 16.0 | | Clindamycin | ≤0.016->32.0 | 0.03 | 1.0 | | Metronidazole | ≤0.125-1.0 | 0.5 | 1.0 | Bacteroides distasonis (5/11) | Sulopenem | 0.25-1.0 | 0.5 | 1.0 | | Imipenem | 0.25-1.0 | 0.5 | 1.0 | | Amoxicillin/clavulanate | 2.0-32.0 | 4.0 | 16.0 | | Ampicillin/sulbactam | 4.0-32.0 | 8.0 | 32.0 | | Piperacillin/tazobactam | 2.0-16.0 | 4.0 | 4.0 | | Clindamycin | 0.03->32.0 | 4.0 | 16.0 | | Metronidazole | 0.5-1.0 | 1.0 | 1.0 | Bacteroides uniformis (6/6) | Sulopenem | 0.25-1.0 | 0.25 | | | Imipenem | 0.25-0.5 | 0.25 | | | Amoxicillin/clavulanate | 0.5-16.0 | 0.5 | | | Ampicillin/sulbactam | 1.0-32.0 | 1.0 | | | Piperacillin/tazobactam | 0.5-8.0 | 1.0 | | | Clindamycin | 1.0->32.0 | 2.0 | | | Metronidazole | 0.5-1.0 | 0.5 | | Bacteroides stercoris (5/5) | Sulopenem | 0.25-0.5 | 0.25 | | | Imipenem | 0.25-0.5 | 0.25 | | | Amoxicillin/clavulanate | 0.5-2.0 | 1.0 | | | Ampicillin/sulbactam | 1.0-4.0 | 2.0 | | | Piperacillin/tazobactam | ≤0.125-4.0 | 1.0 | | | Clindamycin | 4->32.0 | 8.0 | | | Metronidazole | 1.0-2.0 | 1.0 | | Prevotella bivia (12/16) | Sulopenem | 0.06-0.5 | 0.125 | 0.25 | | Imipenem | 0.03-0.25 | 0.03 | 0.25 | | Amoxicillin/clavulanate | ≤0.125-4.0 | 0.5 | 4.0 | | Ampicillin/sulbactam | ≤0.125-8.0 | 1.0 | 4.0 | | Piperacillin/tazobactam | ≤0.125-4.0 | ≤0.125 | ≤0.125 | | Clindamycin | ≤0.016->32.0 | ≤0.016 | >32.0 | | Metronidazole | 1.0-4.0 | 2.0 | 4.0 | Prevotella buccae (8/16) | Sulopenem | 0.06-0.25 | 0.125 | 0.25 | | Imipenem | 0.03-0.125 | 0.03 | 0.125 | | Amoxicillin/clavulanate | ≤0.125-2.0 | ≤0.125 | 1.0 | | Ampicillin/sulbactam | ≤0.125-2.0 | 0.25 | 2.0 | | Piperacillin/tazobactam | ≤0.125 | ≤0.125 | ≤0.125 | | Clindamycin | ≤0.016 | ≤0.016 | ≤0.016 | | Metronidazole | 0.5-2.0 | 1.0 | 2.0 | Prevotella melaninogenica/P. denticola (12/17) | Sulopenem | 0.03-0.25 | 0.125 | 0.25 | | Imipenem | ≤0.016-0.125 | 0.03 | 0.125 | | Amoxicillin/clavulanate | ≤0.125-2.0 | 0.25 | 2.0 | | Ampicillin/sulbactam | ≤0.125-4.0 | 0.5 | 2.0 | | Piperacillin/tazobactam | ≤0.125 | ≤0.125 | ≤0.125 | | Clindamycin | ≤0.016-0.125 | ≤0.016 | 0.06 | | Metronidazole | ≤0.125-1.0 | 0.5 | 1.0 | Prevotella intermedia/P. nigrescens (8/13) | Sulopenem | 0.03-0.125 | 0.06 | 0.125 | | Imipenem | ≤0.016-0.06 | ≤0.016 | 0.06 | | Amoxicillin/clavulanate | ≤0.125-0.5 | ≤0.125 | 0.5 | | Ampicillin/sulbactam | ≤0.125-1.0 | 0.25 | 0.5 | | Piperacillin/tazobactam | ≤0.125 | ≤0.125 | ≤0.125 | | Clindamycin | ≤0.016-8.0 | ≤0.016 | ≤0.016 | | Metronidazole | ≤0.125-1.0 | 0.5 | 1.0 | Prevotella corporis (4/9) | Sulopenem | 0.03-0.125 | 0.06 | | | Imipenem | ≤0.016-0.06 | ≤0.016 | | | Amoxicillin/clavulanate | ≤0.125-0.5 | ≤0.125 | | | Ampicillin/sulbactam | ≤0.125-2.0 | ≤0.125 | | | Piperacillin/tazobactam | ≤0.125 | ≤0.125 | | | Clindamycin | ≤0.016->32.0 | ≤0.016 | | | Metronidazole | ≤0.125-1.0 | 0.5 | | Prevotella disiens (6/7) | Sulopenem | 0.03-0.25 | 0.125 | | | Imipenem | 0.03-0.125 | 0.06 | | | Amoxicillin/clavulanate | ≤0.125-2.0 | 0.25 | | | Ampicillin/sulbactam | ≤0.125-2.0 | 0.25 | | | Piperacillin/tazobactam | ≤0.125 | ≤0.125 | | | Clindamycin | ≤0.016-0.03 | ≤0.016 | | | Metronidazole | 1.0-2.0 | 1.0 | | Prevotella baroniae (0/3) | Sulopenem | 0.06 | | | | Imipenem | 0.03 | | | | Amoxicillin/clavulanate | ≤0.125 | | | | Ampicillin/sulbactam | ≤0.125 | | | | Piperacillin/tazobactam | ≤0.125 | | | | Clindamycin | ≤0.016->32.0 | | | | Metronidazole | 0.5-1.0 | | | Prevotella oralis group (1/3) | Sulopenem | ≤0.016-0.125 | | | | Imipenem | ≤0.016-0.06 | | | | Amoxicillin/clavulanate | ≤0.125-0.5 | | | | Ampicillin/sulbactam | ≤0.125-1.0 | | | | Piperacillin/tazobactam | ≤0.125 | | | | Clindamycin | ≤0.016 | | | | Metronidazole | ≤0.125-1.0 | | | Prevotella veroralis (2/3) | Sulopenem | 0.06-0.125 | | | | Imipenem | 0.03 | | | | Amoxicillin/clavulanate | ≤0.125-0.25 | | | | Ampicillin/sulbactam | ≤0.125-1.0 | | | | Piperacillin/tazobactam | ≤0.125 | | | | Clindamycin | ≤0.016-0.03 | | | | Metronidazole | 0.25-0.5 | | | Prevotella bergensis (2/2) | Sulopenem | 0.125 | | | | Imipenem | 0.06 | | | | Amoxicillin/clavulanate | 0.5 | | | | Ampicillin/sulbactam | 1.0 | | | | Piperacillin/tazobactam | ≤0.125 | | | | Clindamycin | ≤0.016-0.25 | | | | Metronidazole | 0.5 | | | Prevotella salivae (1/2) | Sulopenem | 0.06-0.125 | | | | Imipenem | 0.03-0.06 | | | | Amoxicillin/clavulanate | ≤0.125-0.5 | | | | Ampicillin/sulbactam | ≤0.125-1.0 | | | | Piperacillin/tazobactam | ≤0.125 | | | | Clindamycin | ≤0.016 | | | | Metronidazole | ≤0.125-0.5 | | | Prevotella loescheii (1/1) | Sulopenem | 0.125 | | | | Imipenem | 0.03 | | | | Amoxicillin/clavulanate | 0.25 | | | | Ampicillin/sulbactam | 0.5 | | | | Piperacillin/tazobactam | ≤0.125 | | | | Clindamycin | ≤0.016 | | | | Metronidazole | 0.5 | | | Prevotella sp. (0/1) | Sulopenem | 0.03 | | | | Imipenem | 0.03 | | | | Amoxicillin/clavulanate | ≤0.125 | | | | Ampicillin/sulbactam | ≤0.125 | | | | Piperacillin/tazobactam | ≤0.125 | | | | Clindamycin | ≤0.016 | | | | Metronidazole | 0.5 | | | Porphyromonas asaccharolytica (0/4) | Sulopenem | ≤0.016-0.03 | | | | Imipenem | ≤0.016 | | | | Amoxicillin/clavulanate | ≤0.125 | | | | Ampicillin/sulbactam | ≤0.125 | | | | Piperacillin/tazobactam | ≤0.125 | | | | Clindamycin | ≤0.016->32.0 | | | | Metronidazole | ≤0.125-4.0 | | | Porphyromonas gingivalis (0/3) | Sulopenem | 0.03-0.06 | | | | Imipenem | ≤0.016 | | | | Amoxicillin/clavulanate | ≤0.125 | | | | Ampicillin/sulbactam | ≤0.125 | | | | Piperacillin/tazobactam | ≤0.125 | | | | Clindamycin | ≤0.016 | | | | Metronidazole | ≤0.125 | | | Fusobacterium nucleatum (1/20) | Sulopenem | ≤0.016-0.06 | ≤0.016 | 0.03 | | Imipenem | ≤0.016-0.06 | 0.03 | 0.06 | | Amoxicillin/clavulanate | ≤0.125-1.0 | ≤0.125 | ≤0.125 | | Ampicillin/sulbactam | ≤0.125-8.0 | ≤0.125 | ≤0.125 | | Piperacillin/tazobactam | ≤0.125 | ≤0.125 | ≤0.125 | | Clindamycin | ≤0.016-0.125 | 0.06 | 0.125 | | Metronidazole | ≤0.125-0.5 | ≤0.125 | 0.5 | Fusobacterium necrophorum (0/5) | Sulopenem | ≤0.016 | ≤0.016 | | | Imipenem | ≤0.016 | ≤0.016 | | | Amoxicillin/clavulanate | ≤0.125 | ≤0.125 | | | Ampicillin/sulbactam | ≤0.125 | ≤0.125 | | | Piperacillin/tazobactam | ≤0.125 | ≤0.125 | | | Clindamycin | ≤0.016-0.06 | 0.03 | | | Metronidazole | ≤0.125-0.25 | 0.25 | | Fusobacterium mortiferum (2/14) | Sulopenem | 0.125-1.0 | 0.5 | 0.5 | | Imipenem | 0.25-1.0 | 0.5 | 1.0 | | Amoxicillin/clavulanate | 0.5-32.0 | 1.0 | 32.0 | | Ampicillin/sulbactam | 0.5->32.0 | 1.0 | >32.0 | | Piperacillin/tazobactam | 0.25-8.0 | 0.25 | 1.0 | | Clindamycin | 0.03-0.25 | 0.06 | 0.125 | | Metronidazole | ≤0.125-1.0 | 0.25 | 0.5 | Fusobacterium varium (0/21) | Sulopenem | 0.125-0.5 | 0.5 | 0.5 | | Imipenem | 0.5-1.0 | 0.5 | 1.0 | | Amoxicillin/clavulanate | 1.0-2.0 | 2.0 | 2.0 | | Ampicillin/sulbactam | 0.5-2.0 | 2.0 | 2.0 | | Piperacillin/tazobactam | 1.0-8.0 | 4.0 | 8.0 | | Clindamycin | 1.0-32.0 | 8.0 | 32.0 | | Metronidazole | ≤0.125-1.0 | 0.25 | 0.5 | Finegoldia magna (0/10) | Sulopenem | 0.125-0.5 | 0.25 | 0.25 | | Imipenem | 0.06-0.125 | 0.06 | 0.125 | | Amoxicillin/clavulanate | ≤0.125-0.5 | 0.25 | 0.25 | | Ampicillin/sulbactam | ≤0.125-0.5 | 0.25 | 0.5 | | Piperacillin/tazobactam | ≤0.125-0.25 | ≤0.125 | 0.25 | | Clindamycin | 0.06->32.0 | 0.125 | 2.0 | | Metronidazole | 0.25-1.0 | 0.5 | 1.0 | Micromonas micros (0/10) | Sulopenem | 0.125-0.25 | 0.125 | 0.125 | | Imipenem | 0.03-0.125 | 0.03 | 0.06 | | Amoxicillin/clavulanate | ≤0.125-2.0 | ≤0.125 | 0.5 | | Ampicillin/sulbactam | ≤0.125-1.0 | ≤0.125 | 1.0 | | Piperacillin/tazobactam | ≤0.125-0.25 | ≤0.125 | ≤0.125 | | Clindamycin | 0.125-0.5 | 0.125 | 0.25 | | Metronidazole | ≤0.125-0.5 | 0.25 | 0.5 | Peptostreptococcus anaerobius (0/10) | Sulopenem | 0.25-4.0 | 0.5 | 2.0 | | Imipenem | 0.06-2.0 | 0.06 | 1.0 | | Amoxicillin/clavulanate | ≤0.125-32.0 | 0.25 | 32.0 | | Ampicillin/sulbactam | ≤0.125-16.0 | 0.25 | 16.0 | | Piperacillin/tazobactam | 0.25-16 | 0.25 | 16.0 | | Clindamycin | ≤0.016-0.25 | ≤0.016 | 0.25 | | Metronidazole | ≤0.125-1.0 | 0.5 | 1.0 | Peptoniphilus asaccharolyticus (0/7) | Sulopenem | 0.03-0.06 | 0.06 | | | Imipenem | ≤0.016-0.03 | ≤0.016 | | | Amoxicillin/clavulanate | ≤0.125 | ≤0.125 | | | Ampicillin/sulbactam | ≤0.125 | ≤0.125 | | | Piperacillin/tazobactam | ≤0.125 | ≤0.125 | | | Clindamycin | 0.06->32.0 | 0.125 | | | Metronidazole | ≤0.125-2.0 | 1.0 | | Anaerococcus tetradius (0/10) | Sulopenem | 0.06-1.0 | 0.125 | 0.25 | | Imipenem | ≤0.016-0.5 | 0.03 | 0.06 | | Amoxicillin/clavulanate | ≤0.125-1.0 | ≤0.125 | ≤0.125 | | Ampicillin/sulbactam | ≤0.125-1.0 | ≤0.125 | ≤0.125 | | Piperacillin/tazobactam | ≤0.125-2.0 | ≤0.125 | 0.25 | | Clindamycin | 0.25-1.0 | 0.5 | 1.0 | | Metronidazole | 0.5-2.0 | 1.0 | 1.0 | Anaerococcus prevotii (0/3) | Sulopenem | 0.03-0.125 | | | | Imipenem | ≤0.016-0.03 | | | | Amoxicillin/clavulanate | ≤0.125-0.25 | | | | Ampicillin/sulbactam | ≤0.125-0.25 | | | | Piperacillin/tazobactam | ≤0.125 | | | | Clindamycin | 0.125-0.25 | | | | Metronidazole | 1.0-2.0 | | | Lactobacillus (0/10) | Sulopenem | 0.5->8.0 | >8.0 | >8.0 | | Imipenem | 0.125-4.0 | 1.0 | 2.0 | | Amoxicillin/clavulanate | 0.5-1.0 | 1.0 | 1.0 | | Ampicillin/sulbactam | 0.5-1.0 | 1.0 | 1.0 | | Piperacillin/tazobactam | 1.0-2.0 | 2.0 | 2.0 | | Clindamycin | 0.25-4.0 | 0.5 | 4.0 | | Metronidazole | >16.0 | >16.0 | >16.0 | Bifidobacterium (0/10) | Sulopenem | 0.06-1.0 | 0.25 | 1.0 | | Imipenem | 0.03-0.25 | 0.03 | 0.125 | | Amoxicillin/clavulanate | ≤0.125-0.5 | ≤0.125 | 0.25 | | Ampicillin/sulbactam | ≤0.125-0.5 | ≤0.125 | 0.25 | | Piperacillin/tazobactam | ≤0.125-0.5 | ≤0.125 | 0.25 | | Clindamycin | ≤0.016->32.0 | 0.03 | >32.0 | | Metronidazole | 4->16.0 | >16.0 | >16.0 | Propionibacterium acnes (0/18) | Sulopenem | 0.125-0.25 | 0.125 | 0.25 | | Imipenem | ≤0.016-0.03 | 0.03 | 0.03 | | Amoxicillin/clavulanate | ≤0.125-0.25 | ≤0.125 | 0.25 | | Ampicillin/sulbactam | ≤0.125-0.25 | ≤0.125 | 0.25 | | Piperacillin/tazobactam | ≤0.125-1.0 | 0.25 | 1.0 | | Clindamycin | 0.06 | 0.06 | 0.06 | | Metronidazole | >16.0 | >16.0 | >16.0 | Actinomyces (0/5) | Sulopenem | 0.25-0.5 | 0.5 | | | Imipenem | 0.06-0.25 | 0.125 | | | Amoxicillin/clavulanate | ≤0.125-0.5 | 0.25 | | | Ampicillin/sulbactam | ≤0.125-0.5 | 0.25 | | | Piperacillin/tazobactam | 0.5-2.0 | 1.0 | | | Clindamycin | 0.03-4.0 | 0.125 | | | Metronidazole | 1.0->16.0 | >16.0 | | Eggerthella lenta (0/17) | Sulopenem | 1.0 | 1.0 | 1.0 | | Imipenem | 0.25-0.5 | 0.5 | 0.5 | | Amoxicillin/clavulanate | 0.5-1.0 | 1.0 | 1.0 | | Ampicillin/sulbactam | 0.5-2.0 | 1.0 | 2.0 | | Piperacillin/tazobactam | 8.0-16.0 | 16.0 | 16.0 | | Clindamycin | 0.06->32.0 | 0.25 | 1.0 | | Metronidazole | 0.25-0.5 | 0.5 | 0.5 | Clostridium perfringens (0/19) | Sulopenem | 0.03-0.5 | 0.125 | 0.25 | | Imipenem | 0.06-0.125 | 0.125 | 0.125 | | Amoxicillin/clavulanate | ≤0.125 | ≤0.125 | ≤0.125 | | Ampicillin/sulbactam | ≤0.125-0.25 | ≤0.125 | 0.25 | | Piperacillin/tazobactam | ≤0.125-0.5 | ≤0.125 | 0.5 | | Clindamycin | 0.06->32.0 | 0.5 | 2.0 | | Metronidazole | 0.5-2.0 | 1.0 | 1.0 | Clostridium difficile (0/10) | Sulopenem | 2.0-4.0 | 2.0 | 4.0 | | Imipenem | 2.0-4.0 | 4.0 | 4.0 | | Amoxicillin/clavulanate | 0.5-2.0 | 1.0 | 2.0 | | Ampicillin/sulbactam | 1.0-4.0 | 2.0 | 2.0 | | Piperacillin/tazobactam | 8.0-16.0 | 8.0 | 16.0 | | Clindamycin | 2.0->32.0 | 4.0 | >32.0 | | Metronidazole | 0.25-0.5 | 0.5 | 0.5 | Clostridium sp (0/10) | Sulopenem | 0.06-4.0 | 2.0 | 4.0 | | Imipenem | 0.06-4.0 | 1.0 | 1.0 | | Amoxicillin/clavulanate | ≤0.125-1.0 | 0.5 | 0.5 | | Ampicillin/sulbactam | ≤0.125-0.5 | 0.25 | 0.5 | | Piperacillin/tazobactam | ≤0.125-2.0 | 1.0 | 2.0 | | Clindamycin | 1.0->32.0 | 1.0 | 16.0 | | Metronidazole | 0.25-1.0 | 1.0 | 1.0 | Clostridium tertium (0/5) | Sulopenem | 1.0 | 1.0 | | | Imipenem | 0.25 | 0.25 | | | Amoxicillin/clavulanate | 0.5-1.0 | 0.5 | | | Ampicillin/sulbactam | 0.25-1.0 | 0.25 | | | Piperacillin/tazobactam | 4.0-8.0 | 8.0 | | | Clindamycin | 8.0-16.0 | 8.0 | | | Metronidazole | 0.5-1.0 | 1.0 | | Clostridium ramosum (0/4) | Sulopenem | 0.5 | | | | Imipenem | 0.25-0.5 | | | | Amoxicillin/clavulanate | ≤0.125 | | | | Ampicillin/sulbactam | ≤0.125 | | | | Piperacillin/tazobactam | ≤0.125 | | | | Clindamycin | 2.0-4.0 | | | | Metronidazole | 1.0 | | | Clostridium cadaveris (0/3) | Sulopenem | 0.25 | | | | Imipenem | 0.125 | | | | Amoxicillin/clavulanate | ≤0.125-0.25 | | | | Ampicillin/sulbactam | ≤0.125 | | | | Piperacillin/tazobactam | ≤0.125-0.25 | | | | Clindamycin | 0.06 | | | | Metronidazole | ≤0.125 | | | Clostridium bifermentans (0/2) | Sulopenem | 0.5 | | | | Imipenem | 0.25-0.5 | | | | Amoxicillin/clavulanate | 0.25 | | | | Ampicillin/sulbactam | 0.5 | | | | Piperacillin/tazobactam | 0.5 | | | | Clindamycin | 0.125-0.25 | | | | Metronidazole | 0.25-0.5 | | | Clostridium innocuum (0/2) | Sulopenem | 0.25-4.0 | | | | Imipenem | 0.125-2.0 | | | | Amoxicillin/clavulanate | ≤0.125-1.0 | | | | Ampicillin/sulbactam | ≤0.125-0.25 | | | | Piperacillin/tazobactam | ≤0.125-2.0 | | | | Clindamycin | 0.03-1.0 | | | | Metronidazole | ≤0.125-0.5 | | | Clostridium sordellii (0/2) | Sulopenem | 0.125-0.5 | | | | Imipenem | 0.06-0.125 | | | | Amoxicillin/clavulanate | ≤0.125 | | | | Ampicillin/sulbactam | ≤0.125 | | | | Piperacillin/tazobactam | ≤0.125 | | | | Clindamycin | 0.25-1.0 | | | | Metronidazole | 1.0 | | | Clostridium butyricum (0/1) | Sulopenem | 0.5 | | | | Imipenem | 0.5 | | | | Amoxicillin/clavulanate | 1.0 | | | | Ampicillin/sulbactam | 1.0 | | | | Piperacillin/tazobactam | 0.5 | | | | Clindamycin | 2.0 | | | | Metronidazole | ≤0.125 | | | Clostridium clostridioforme (0/1) | Sulopenem | 1.0 | | | | Imipenem | 1.0 | | | | Amoxicillin/clavulanate | 1.0 | | | | Ampicillin/sulbactam | 1.0 | | | | Piperacillin/tazobactam | 8.0 | | | | Clindamycin | 0.03 | | | | Metronidazole | ≤0.125 | | | Clostridium hastiforme (0/1) | Sulopenem | 2.0 | | | | Imipenem | 2.0 | | | | Amoxicillin/clavulanate | 1.0 | | | | Ampicillin/sulbactam | 1.0 | | | | Piperacillin/tazobactam | 2.0 | | | | Clindamycin | 0.06 | | | | Metronidazole | 0.25 | | | All strains (155/431) | Sulopenem | ≤0.016->8.0 | 0.25 | 1.0 | | Imipenem | ≤0.016-4.0 | 0.06 | 1.0 | | Amoxicillin/clavulanate | ≤0.125-32.0 | 0.5 | 2.0 | | Ampicillin/sulbactam | ≤0.125->32.0 | 0.5 | 4.0 | | Piperacillin/tazobactam | ≤0.125-16.0 | 0.25 | 8.0 | | Clindamycin | ≤0.016->32.0 | 0.25 | 16.0 | | Metronidazole | ≤0.125->16.0 | 1.0 | 4.0 | Open in a separate windowa50% and 90%, MIC 50 and MIC 90, respectively.With the exception of six strains of lactobacilli, sulopenem and imipenem both had MICs of ≤4.0 μg/ml against all strains tested in this study. Clindamycin resistance was found in all of the Bacteroides species tested as well as 5 of the 15 different species of Prevotella and Porphyromonas tested. Eighteen of the 21 strains of Fusbacterium varium showed resistance to clindamycin, while all other fusobacteria were clindamycin susceptible. For all anaerobic gram-positive cocci tested, clindamycin resistance was observed in only one strain of Finegoldia magna and one strain of Peptoniphilus asaccharolyticus. All groups of anaerobic non-spore-forming gram-positive rods except Propionibacterium acnes had some degree of clindamycin resistance. All Clostridium tertium strains as well as some strains in 5 of the 11 other Clostridium species were clindamycin resistant. Most gram-positive non-spore-forming rods (with the exception of Eggerthella) were metronidazole resistant, while all anaerobic gram-negative rods, gram-positive cocci, and clostridia were metronidazole susceptible. Pipercillin/tazobactam was active against all strains tested, with MICs of ≤16 μg/ml. Resistance to amoxicillin/clavulanate was found in four of seven species of Bacteroides as well as two strains of Fusobacterium mortiferum. All other strains of fusobacteria as well as all strains of Prevotella, Porphyromonas, Clostridium, and gram-positive non-spore-forming rods were amoxicillin/clavulanate susceptible. Two of the 10 Peptostreptococcus anaerobius strains showed amoxicillin/clavulanate resistance, while all other gram-positive cocci were susceptible. Ampicillin/sulbactam was active against all strains of Clostridium, anaerobic gram-positive non-spore-forming rods, Prevotella, and Porphyromonas tested. Gram-negative rods showing ampicillin/sulbactam resistance included some strains in three of the seven Bacteroides species tested and two strains of Fusobacterium mortiferum, while other species of fusobacteria were susceptible.While 413 of 431 strains (95.8%) tested had sulopenem MICs of ≤2 μg/ml, 18 strains (4.2%) had MICs of ≥4.0 μg/ml. These included 7 Lactobacillus species (6 strains with >8.0 μg/ml and 1 strain at 4.0 μg/ml), 10 strains of Clostridium (4 C. difficile, 1 C. innocuum, and 5 unspeciated) (MICs all 4.0 μg/ml), and 1 strain of Peptostreptococcus anaerobius (MIC of 4.0 μg/ml). Until pharmacokinetic/pharmacodynamic breakpoints for sulopenem can be established, the clinical significance of these relatively higher sulopenem MICs cannot be established.Gootz and coworkers ( 13) in their 1989 study on CP-65,207, reported on its activity against 84 anaerobes, many of which have since been reclassified. Excluding Peptococcus spp., which are no longer included among clinically significant anaerobic gram-positive cocci in standard manuals ( 16), their results were similar to those obtained in our study. In a study of the comparative activity of sulopenem against a collection of recently isolated gram-positive and -negative aerobic organisms, sulopenem MIC 90s ranged between 0.03 and 1 μg/ml against all clinically significant bacterial species tested. This high in vitro potency was also confirmed by in vitro time-kill studies ( 15). Our study adds anaerobes to the activity spectrum for this drug and suggests a potential place for sulopenem in treatment of mixed anaerobic infections. Pharmacokinetic/pharmacodynamic and experimental animal studies are necessary to further delineate the clinical role of these compounds in treatment of anaerobic infections. 相似文献
4.
The in vitro susceptibilities of 46 Leptospira isolates from rats to 14 antimicrobial agents were tested. All of the strains were found to be sensitive to ampicillin, cefotaxime, ciprofloxacin, norfloxacin, doxycycline, erythromycin, and streptomycin. In contrast, the tested isolates showed resistance to amphotericin B, 5-fluorouracil, fosfomycin, trimethoprim, sulfamethoxazole, neomycin, and vancomycin. These findings will help in selecting effective and ineffective antimicrobials for treatment of leptospirosis and for the development of new selective media, respectively.Pathogenic Leptospira species, spirochetes of the genus Leptospira, are the causative agents of leptospirosis, a zoonotic disease with a worldwide distribution. These bacteria are carried by a variety of animal species in their kidney tubules and contaminate the environment by being shed in urine ( 2). Contact with this contaminated environment is one of the important pathways of transmission of the disease. Although this disease is associated with remarkable rates of mortality and morbidity in both animals and humans, diagnosis is often difficult due to nonspecific clinical presentation and limitations in laboratory tests. Due to these difficulties, clinically suspected cases are usually treated by empirical chemotherapy, for which information about the susceptibilities of Leptospira isolates against various antimicrobial agents is required. Several studies have been reported previously regarding the susceptibilities of Leptospira isolates to a large number of antimicrobial agents ( 6, 8, 11, 12, 15, 18, 19). However, most of these reports used laboratory-passaged strains. Studies revealing the sensitivities of clinical and environmental isolates are few ( 18, 19) and limited by the use of a small number of strains.In comparison with the available data on effective antimicrobials, published data reporting agents that are ineffective against Leptospira strains are rare. For improving the isolation of leptospires from contaminated samples, information regarding ineffective antimicrobials is helpful in the selection of agents to prevent the usual contamination in Leptospira cultures.In the present study, we determined the susceptibilities of 46 Leptospira strains to 14 antimicrobials, including both effective and ineffective agents. To screen for sensitivity to antimicrobials, we performed MIC assays of aminobenzyl penicillin (ampicillin), new quinolone (ciprofloxacin and norfloxacin), tetracycline (doxycycline), aminoglycoside (streptomycin), macrolide (erythromycin), and expanded-spectrum cephalosporin (cefotaxime) for these strains. Among the tested antimicrobials, penicillins, doxycycline, and broad-spectrum cephalosporins are widely used for the treatment of leptospirosis ( 2, 17, 25). The other drugs were also found to be effective against Leptospira isolates in several in vitro ( 6, 8, 11, 12, 15, 18, 19) and in vivo ( 3, 5, 17, 20, 21, 22) studies.To test susceptibility to ineffective agents, we selected 5-fluorouracil, fosfomycin, neomycin, and vancomycin due to their usage in selective media for culture of Leptospira isolates ( 1, 7, 13, 14, 16, 23). We also included amphotericin B for its antifungal effect and trimethoprim-sulfamethoxazole due to their use in the selective medium of another spirochete, Borrelia ( 10).The Leptospira strains used in this study were collected from rats in Metro Manila and Laguna, Philippines, from August 2006 to May 2007 ( 24). During isolation, Ellinghausen-McCullough-Johnson-Harris (EMJH) and Korthof''s media supplemented with 5-fluorouracil were used for primary culture of the rat kidneys. These isolates were classified as Leptospira interrogans serovar Manilae, serovar Losbanos, and serogroup Grippotyphosa and Leptospira borgpetersenii serogroup Javanica (see Table S1 in the supplemental material). Of the 46 strains, 34 were lethal in experimental infections of golden hamsters ( 24). All of these isolates had undergone fewer than 10 in vitro passages before our experiment. Both Korthof''s and EMJH medium ( 2, 25) were used for subculturing the strains. To compare the validity of our test with the results of previous reports, we used Leptospira interrogans strain Ictero No. 1 (serovar Icterohaemorrhagiae), which was maintained in our laboratory through continuous passages in Korthof''s medium. For preparing the inocula, cultures were grown at 30°C for 7 days and enumerated in a Thoma counting chamber under dark-field microscopy.The antimicrobial agents were purchased from Sigma-Aldrich, except for trimethoprim (Wako Pure Chemical Industries Ltd., Tokyo, Japan). To prepare the stock solutions, antimicrobials were dissolved in sterile distilled water, except that ciprofloxacin and norfloxacin were dissolved in 0.1 N NaOH, erythromycin, sulfamethoxazole, and trimethoprim in 95% ethanol, and amphotericin B in dimethyl sulfoxide. Further dilutions of these agents were done with either sterile distilled water or Leptospira media. The stock solutions were stored at −80°C in one-time-use aliquots.The broth microdilution method was performed as previously described by Murray and Hospenthal ( 11). The MICs were noted visually as the lowest concentration of antimicrobials in the wells without color change of alamar blue from blue to pink/purple. We repeated this test at least twice for each strain, and the MIC of cefotaxime for strain K56 was confirmed in three repeated tests. The results were reproducible for each antimicrobial-strain combination.Results showing the distribution of MIC values are displayed in two groups: effective and ineffective antimicrobials are shown in Table and in Table , respectively. The MIC 50s and MIC 90s of the strains are included in the tables. From our results, all of the strains were found to be sensitive to ampicillin, ciprofloxacin, doxycycline, erythromycin, and streptomycin, which correlates with previous studies ( 6, 8, 11, 12, 15, 18, 19). Norfloxacin, which has not been tested before for antileptospiral activity, was also found to be effective against these strains (Table ). As resistance to ciprofloxacin is rapidly emerging among Escherichia coli and other enteric bacteria ( 4, 9), this finding supports the use of norfloxacin instead of ciprofloxacin as an alternative choice in empirical therapy. In the case of cefotaxime, though most of the strains showed sensitivity, the MICs for a few strains were higher than in the previous reports. This reduced effectiveness of cefotaxime against some strains requires further investigation to survey the development of resistance of Leptospira strains against this potent antileptospiral agent. Regardless of this finding, all of these antimicrobials were found to have potential as chemotherapeutic agents for leptospirosis due to their high efficacies, lower costs, and eligibility for empirical therapy. TABLE 1.Distribution of MICs of ampicillin, cefotaxime, ciprofloxacin, norfloxacin, doxycycline, erythromycin, and streptomycin among the Leptospira strains Antimicrobiala | No. of strains with MIC (μg/ml) of:
| Mean MIC | MIC50 | MIC90 |
---|
<0.01 | 0.01 | 0.02 | 0.04 | 0.08 | 0.16 | 0.31 | 0.63 | 1.25 | 2.5 | 5 |
---|
ABPC | 1 | 1 | 11 | 22 | 4 | 2 | 4 | 1 | | | | 0.05 | 0.04 | 0.31 | CTX | | | | 1 | 1 | 17 | 11 | 8 | 7 | | 1 | 0.19 | 0.31 | 1.25 | CPFX | | | | | 1 | 23 | 21 | 1 | | | | 0.22 | 0.16 | 0.31 | NFLX | | | | 1 | | | 2 | 11 | 27 | 3 | | 0.83 | 1.25 | 1.25 | DOXY | | | 1 | 10 | 13 | 11 | 8 | 2 | 1 | | | 0.12 | 0.08 | 0.31 | EM | 13 | 21 | 9 | 1 | | 1 | 1 | | | | | 0.01 | 0.01 | 0.02 | SM | | | | | | | 1 | 1 | 12 | 20 | 12 | 2.37 | 2.5 | 5 | Open in a separate windowaABPC, ampicillin; CTX, cefotaxime; CPFX, ciprofloxacin; NFLX, norfloxacin; DOXY, doxycycline; EM, erythromycin; SM, streptomycin. TABLE 2.Distribution of MICs of amphotericin B, 5-fluorouracil, neomycin, fosfomycin, sulfamethoxazole, trimethoprim, and vancomycin among the Leptospira strains Antimicrobiala | No. of strains with MIC (μg/ml) of:
| Mean MIC | MIC90 | MIC90 |
---|
6.25 | 12.5 | 25 | 50 | 100 | 200 | 400 | 800 | ≥1,600 |
---|
AMPH-B | | | | | | | | 1 | 45 | 1,577 | ≥1,600 | ≥1,600 | 5-FU | | | | | | | | 3 | 43 | 1,524 | ≥1,600 | ≥1,600 | NEO | 1 | 3 | 15 | 10 | 4 | 11 | 2 | | | 56 | 50 | 200 | FOM | | | | | | | | 2 | 44 | 1,556 | ≥1,600 | ≥1,600 | SMX | | | | | | 1 | 5 | 2 | 37 | 1,204 | ≥1,600 | ≥1,600 | TMP | | | | | | | 1 | 1 | 44 | 1,524 | ≥1,600 | ≥1,600 | VCM | | | 4 | 6 | 11 | 11 | 14 | | | 290 | 200 | 400 | Open in a separate windowaAMPH-B, amphotericin B; 5-FU, 5-fluorouracil; NEO, neomycin; FOM, fosfomycin; SMX, sulfamethoxazole; TMP, trimethoprim; VCM, vancomycin.In contrast to the findings discussed above, the Leptospira strains tested were found to be highly resistant to amphotericin B, 5-fluorouracil, fosfomycin, sulfamethoxazole, and trimethoprim (Table ). Compared to the levels of resistance to these five ineffective agents, the levels of resistance to neomycin and vancomycin were highly variable. The high degrees of ineffectiveness of amphotericin B, 5-fluorouracil, fosfomycin, sulfamethoxazole, and trimethoprim against Leptospira isolates, together with their broad spectrum of antimicrobial activities, strongly support the usefulness of these agents to inhibit the growth of contaminants in Leptospira selective media. Regarding this aspect, the indications for and appropriate concentrations of neomycin and vancomycin should be considered cautiously due to their wide range of strain sensitivities.In this study, we report the effectiveness and ineffectiveness of various antimicrobials against a large number of Leptospira isolates collected from rats, a key animal reservoir of Leptospira species. Our findings, which explore sensitivity and resistance, the two opposite phenomena in drug-pathogen interactions, will be helpful in filling the gaps in knowledge in the arena of treatment and in the difficulties of isolating Leptospira bacteria. 相似文献
5.
One hundred fifty canine and feline Escherichia coli isolates associated with urinary tract infections were screened for the presence of extended-spectrum β-lactamase (ESBL) genes. Out of 60 isolates suspected to be ESBL positive based on antimicrobial susceptibility testing, 11 ESBLs were identified, including one SHV-12 gene, one CTX-M-14 gene, and nine CTX-M-15 genes. This study provides the first report of CTX-M- and SHV-type ESBLs in dogs and cats in the United States.The first detection of an extended-spectrum β-lactamase (ESBL) in an organism from an animal was reported in Japan in 1988 in an Escherichia coli isolate from a laboratory dog ( 13). Since that time, numerous reports of ESBL-positive isolates from dogs and cats, as well as from other animal species ( 5), have been made worldwide ( 4, 8, 11, 17, 25, 26). Only one study has identified the presence of an ESBL in isolates from animals in the United States, i.e., in Salmonella enterica serovar Newport from horses ( 21). We hypothesized that ESBL genes would be present in urinary E. coli isolates from companion animals in the United States. The purpose of this study was to screen a group of 150 E. coli isolates from canine and feline patients that had been diagnosed with a urinary tract infection (UTI) for the presence of ESBL genes.A convenience sample of 150 E. coli isolates collected from canine and feline patients at the Matthew J. Ryan Veterinary Hospital of the University of Pennsylvania with clinical signs or evidence on routine urinalysis of a UTI between 1 September 2004 and 31 December 2007 was used in this study. Isolates were frozen in Microbank tubes (ProLab Diagnostics, Austin, TX) and stored at −70°C prior to use.MICs were determined using a Negative Combo 31 panel on a MicroScan Walkaway 40 (Dade Behring, Siemens Healthcare Diagnostics, Deerfield, IL). Results were interpreted using Clinical and Laboratory Standards Institute (CLSI) breakpoints ( 7). Isolates collected from the same individual animal within a 45-day period were considered to be the same strain, and only the first isolate collected was analyzed (subsequent isolates were considered redundant). All isolates with a cefpodoxime MIC of ≥4 μg/ml and a ceftazidime MIC of ≥1 μg/ml were identified as an “ESBL alert” on the MicroScan Walkaway. ESBL confirmatory testing was performed via the Etest method using ceftazidime-ceftazidime-clavulanic acid and cefotaxime-cefotaxime-clavulanic acid strips in accordance with CLSI guidelines ( 7).Due to the high prevalence of cefoxitin resistance in this population, PCR was performed to detect the presence of a blaAmpC gene, the product of which can mask the effects of clavulanic acid on the ESBL confirmatory test ( 18, 27). Since the primers used in this study to identify the blaAmpC gene ( 18) have since been shown to amplify the plasmid-mediated blaCMY gene from Citrobacter freundii ( 19), it can be inferred that the genes detected were part of the blaCMY lineage. Salmonella Newport strain 0007-33 was used as the positive control ( 21). PCR was performed for the genes blaTEM, blaSHV, and blaCTX-M as published previously ( 9, 10, 27). Salmonella Newport strain 0007-33 was also used as the TEM and SHV positive control ( 21), and E. coli strain MISC 336 (CTX-M-1 positive) was used as the CTX-M positive control.The blaTEM, blaSHV, and blaCTX-M PCR products were sequenced using both strands of DNA for each PCR product. Protein sequences were aligned using Lasergene software (DNASTAR, Inc., Madison, WI) and included GenBank sequences ( http://www.ncbi.nlm.nih.gov/GenBank/index.html) to confirm ESBL genotype. Mutations were evaluated with reference to the Lahey Clinic website ( http://www.lahey.org/studies/). GenBank accession numbers used for alignment of protein sequences were {"type":"entrez-protein","attrs":{"text":"AAR25033","term_id":"38606069","term_text":"AAR25033"}}AAR25033 for TEM-1 and {"type":"entrez-protein","attrs":{"text":"ABF29674","term_id":"94502886","term_text":"ABF29674"}}ABF29674 for SHV-2. CTX-M accession numbers were derived from a list on the Lahey Clinic website. Specific primers for the CTX-M-1 group (M13U and M13L) were used to amplify the entire coding sequences of these blaCTX-M genes ( 23). Sequencing and analysis were carried out as described above to identify the specific CTX-M subtype.Seventy of the 150 E. coli isolates had an “ESBL alert” on the MicroScan Walkaway, and after removal of redundant isolates, 60 isolates were tested further. ESBL confirmatory testing was positive for six of these 60 isolates (Table , column 3). TABLE 1.Distribution of β-lactamase and extended-spectrum β-lactamase genes Isolate | Species | ESBL test | blaCMY | blaSHV | blaTEM | blaCTX-M |
---|
1 | Canine | + | − | SHV-12 | TEM-1 | − | 3 | Canine | − | + | − | − | − | 6 | Canine | − | + | − | TEM-1 | − | 11 | Canine | − | + | − | TEM-1 | − | 17 | Canine | − | + | − | TEM-1 | − | 19 | Canine | − | + | − | − | − | 21 | Feline | + | − | − | − | CTX-M-15 | 26 | Canine | − | + | − | TEM-1 | − | 27 | Canine | − | + | − | TEM-1 | − | 31 | Canine | − | + | − | TEM-1 | − | 32 | Canine | − | + | − | TEM-1 | − | 33 | Canine | − | + | − | − | − | 41 | Canine | − | + | − | TEM-1 | − | 42 | Canine | − | + | − | − | − | 44 | Canine | − | + | − | TEM-1 | − | 53 | Canine | − | + | − | − | − | 57 | Feline | − | + | − | − | − | 62 | Canine | − | + | − | TEM-1 | − | 67 | Canine | − | + | − | − | − | 74 | Canine | − | + | − | TEM-1 | − | 75 | Feline | + | − | − | TEM-1 | CTX-M-15 | 82 | Feline | − | + | − | TEM-1 | − | 85 | Canine | − | + | − | TEM-1 | − | 86 | Canine | − | + | − | TEM-1 | − | 87 | Canine | − | + | − | − | − | 88 | Feline | − | + | − | − | − | 91 | Canine | − | + | − | − | − | 98 | Canine | − | + | − | TEM-1 | − | 102 | Canine | − | + | − | − | − | 104 | Canine | − | + | − | − | − | 112 | Canine | − | + | − | TEM-1 | − | 119 | Canine | − | + | − | − | − | 131 | Canine | − | − | Not done | Not done | Not done | 133 | Feline | − | + | − | − | − | 138 | Feline | − | + | − | TEM-1 | − | 147 | Canine | − | + | − | TEM-1 | − | 149 | Feline | − | + | − | TEM-1 | − | 157 | Canine | + | − | − | − | CTX-M-15 | 165 | Canine | − | + | − | TEM-1 | − | 166 | Canine | − | + | − | TEM-1 | − | 168 | Canine | − | + | − | − | − | 182 | Canine | − | + | − | − | − | 183 | Feline | − | + | − | TEM-1 | − | 190 | Feline | − | + | − | TEM-1 | − | 205 | Canine | − | + | − | TEM-1 | − | 209 | Canine | − | + | − | TEM-1 | − | 210 | Canine | − | + | − | − | − | 219 | Feline | − | + | − | TEM-1 | CTX-M-15 | 220 | Canine | + | − | − | TEM-1 | CTX-M-15 | 230 | Canine | − | + | − | TEM-1 | − | 234 | Canine | − | + | − | TEM-1 | − | 236 | Canine | + | − | − | TEM-1 | CTX-M-14 | 240 | Canine | − | + | − | TEM-1 | − | 242 | Canine | − | + | − | TEM-1 | CTX-M-15 | 246 | Feline | − | + | − | − | CTX-M-15 | 265 | Canine | − | + | − | TEM-1 | CTX-M-15 | 266 | Canine | − | + | − | TEM-1 | − | 267 | Canine | − | + | − | − | CTX-M-15 | 268 | Canine | − | + | − | − | − | 269 | Canine | − | + | − | − | − | Open in a separate windowFifty-three of the 60 isolates were positive for the blaCMY gene (43 canine and 10 feline samples) (Table , column 4). Of the seven negative isolates, six were those previously found to be positive for ESBL production via ESBL testing. The remaining canine isolate (isolate 131, negative for both blaCMY PCR and ESBL testing) was not analyzed further.A total of 40 E. coli isolates were found to carry one or more β-lactamase genes. PCR detected a blaSHV gene in one canine isolate, a blaTEM gene in 29 canine and seven feline isolates, and a blaCTX-M gene in six canine and four feline isolates. The remaining 19 isolates were confirmed as negative for blaSHV, blaTEM, and blaCTX-M genes (Table , columns 5 to 7).Based on sequence analysis (Table , column 5), the one SHV-positive strain (isolate 1) was determined to carry SHV-12. All 36 strains positive for a TEM gene were identified as carrying TEM-1 (Table , column 6). Nine of 10 strains positive for a CTX-M gene carried genes of the CTX-M-1 group. The final strain (isolate 236) was concluded to carry CTX-M-14, given the presence of mutations in the amplified consensus sequence unique to CTX-M-14. DNA from each of the nine CTX-M-1 group strains was amplified using the CTX-M-1 group-specific primer set ( 23). Sequence analysis identified all nine strains as carrying CTX-M-15 (Table , column 7).The CTX-M-type ESBLs identified in this study provide evidence for the dissemination of these genes in the United States. The CTX-M-1 group has frequently been reported in animals in countries other than the United States ( 2, 4, 8, 11, 17). The CTX-M-15 gene has not been identified in any bacterial isolate from animals in the United States. Animal sources of this gene have been identified only in E. coli isolated from the cloacae of Belgian poultry and an E. coli isolate from the urine of a cow in France ( 14, 24). The presence of CTX-M-14 genes in the Enterobacteriaceae has also been documented across the globe ( 22), including in six E. coli strains isolated from the feces of dogs in Chile ( 17). The CTX-M-14 gene identified in this study is the first identified from an animal in the United States and the first linked to a clinical case of UTI in a dog. The SHV-12 gene has been detected in bacterial isolates from animals in several countries ( 1, 4, 6, 26), including, in 2005, a Salmonella enterica serovar Newport strain from a horse in the United States ( 21).Interestingly, of the 11 ESBL-positive isolates identified by sequence analysis, only six were positive by ESBL confirmatory testing, likely due to the concurrent presence of a blaCMY gene in the other five isolates. The product of this gene is known to mask the effects of clavulanic acid on the ESBL confirmatory test ( 28). By relying on ESBL confirmatory testing alone, it is likely that the prevalence of ESBLs is being underestimated, particularly in populations with a high frequency of blaAmpC, such as in the current study. During the study period, E. coli was isolated from samples submitted to our laboratory from 1,318 individual animals, and of these, 257 met the criteria for ESBL confirmatory testing. Of the 257 isolates tested, 14 (5%) were identified as being ESBL producers based on the Etest method, including the six reported in this study. The overall prevalence of E. coli isolates that were positive for an ESBL during this period was 1% (S. Rankin, unpublished observations). It is possible that this is an underestimation, based on the high frequency of blaCMY detected in this study.Though, historically, the most common ESBLs in the United States have been TEM and SHV types ( 16, 20), more recent studies have identified CTX-M genes, first reported in 2003 ( 15). CTX-M ESBLs now predominate in some U.S. health care systems ( 12). The findings from the current study are in agreement with current trends in the United States and other parts of the world ( 3). This study is the first report of E. coli strains that encode SHV-12, CTX-M-15, and CTX-M-14 ESBL genes in companion animals in the United States. 相似文献
6.
We evaluated the pharmacokinetics and safety of the antimicrobial agent triclosan after dermal application of a 2% triclosan-containing cream to six volunteers. Percutaneous absorption calculated from urinary excretion was 5.9% ± 2.1% of the dose (mean ± standard deviation). The amount absorbed suggests that daily application of a standard adult dose would result in a systemic exposure 890 times lower than the relevant no-observed-adverse-effect level. Triclosan can be considered safe for use in hydrophobic creams.Triclosan is an antimicrobial agent with broad-spectrum activity against Gram-positive and Gram-negative bacteria as well as some molds and yeasts. It is bacteriostatic at low concentrations as it blocks lipid synthesis, whereas at higher concentrations (as reached in dermatological preparations) membrane destabilization and triclosan-induced K + leakage lead to a rapid bactericidal effect ( 9, 16). Furthermore, triclosan potently inhibits the growth of Toxoplasma gondii and Plasmodium ( 13, 20) and shows anti-inflammatory effects after topical administration ( 11, 19).For more than 20 years, triclosan has been used widely worldwide in medical and consumer products ( 5, 21). In dermatological preparations, it is an effective topical antiseptic to reduce colonization with Staphylococcus aureus and to treat superinfected atopic dermatitis ( 2, 8, 10, 22). Despite the almost-ubiquitous occurrence of the substance, pharmacokinetic studies are sparse.We evaluated the pharmacokinetics and safety of triclosan in a clinical study in six healthy Caucasians. The study was approved by the Ethics Committee of the University of Cologne and by the competent German authorities, and all participants gave their written informed consent. Demographic baseline characteristics are shown in Table . The study medication (provided by Infectopharm) was a hydrophobic cream containing 2% triclosan. Its composition corresponds to a dermatological standard preparation (NRF 11.122) which is listed in the Neues Rezeptur Formularium (German List of Recommended Standard Formulations). Approximately 60 g of the cream was massaged into the skin of the whole body except for the head and genitals. Exposure was ended by taking a shower 12 h after administration. The subjects were confined to the clinical ward under standardized conditions from 10 h prior until 48 h after study drug administration. TABLE 1.Baseline characteristics of all subjects aSubject no. | Sex | Age (yr) | Body ht (cm) | Body wt (kg) |
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1 | Female | 34 | 171 | 58.3 | 2 | Male | 27 | 187 | 72.0 | 3 | Female | 38 | 168 | 57.3 | 4 | Male | 35 | 171 | 69.5 | 5 | Female | 32 | 181 | 70.6 | 6 | Male | 29 | 181 | 70.0 | Arithmetic mean | | 32.5 | 175.6 | 66.3 | Arithmetic SD | | 4.0 | 5.6 | 6.6 | Open in a separate windowaCharacteristics at prestudy examination ( n = 6 study subjects).Urinary excretion during individual sampling intervals up to 168 h postdose was used for pharmacokinetic calculations (WinNonlin version 5.01). For quantification, the sum of free triclosan and its glucuronide and sulfate metabolites (after enzymatic hydrolysis) was determined using a specific and sensitive high-performance liquid chromatography-mass spectrometry approach based on published methods ( 15, 18). The lower and upper limits of quantification were 4.5 and 800 μg/ml, respectively. Quality control samples showed good precision and accuracy throughout the measurement of study samples.In all individuals, the major fraction of absorbed triclosan was excreted within the first 24 h, and the lower limit of quantification was reached 48 h postdose. The mean amount excreted from 0 to 48 h (Ae 0-48) for triclosan was 57.3 mg, which is 4.9% of the administered dose (Table ). The estimated mean Ae 0-∞ was 68.7 mg, i.e., 5.9% of the dose (in the following discussion, the estimated mean Ae 0-∞ is considered the dose absorbed). The mean apparent terminal elimination half-life ( t1/2λz) was 10.8 h. This is consistent with the results of Sandborgh-Englund et al., who found a median urinary excretion half-life of 11 h after oral intake of triclosan ( 17). The maximal excretion rate, tmaxrate, was observed after 11.0 h. For a complete listing of pharmacokinetic data, see Table . TABLE 2.Individual pharmacokinetic variables for triclosan following administration of approximately 60 g of a hydrophobic dermatological preparation containing 2% triclosan aSubject no. | Dose administeredb (mg of triclosan) | Ae0-48
| Estimated Ae0-∞ (dose absorbed)c
| tmaxrate (h) | t1/2λz (h) |
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In mg | As % of dose | In mg | As % of dose |
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1 | 1,164 | 61.0 | 5.2 | 105.6 | 9.1 | 10.0 | 22.1 | 2 | 1,154 | 57.7 | 5.0 | 59.2 | 5.1 | 19.9 | 3.3 | 3 | 1,150 | 34.0 | 3.0 | 37.9 | 3.3 | 10.0 | 10.9 | 4 | 1,170 | 66.2 | 5.7 | 71.6 | 6.1 | 10.0 | 11.6 | 5 | 1,170 | 38.6 | 3.3 | 49.4 | 4.2 | 10.0 | 8.2 | 6 | 1,186 | 86.4 | 7.3 | 88.6 | 7.5 | 6.0 | 8.5 | Mean | 1,166 | 57.3 | 4.9 | 68.7 | 5.9 | 11.0 | 10.8 | SD | 13 | 19.1 | 1.6 | 25.2 | 2.1 | 4.7 | 6.3 | CV % | 1.1 | 33.4 | 32.5 | 36.7 | 36.2 | 42.6 | 58.2 | Median | 1,167 | 59.3 | 5.1 | 65.4 | 5.6 | 10.0 | 9.7 | Minimum | 1,150 | 34.0 | 3.0 | 37.9 | 3.3 | 6.0 | 3.3 | Maximum | 1,186 | 86.4 | 7.3 | 105.6 | 9.1 | 19.9 | 22.1 | Open in a separate windowaCalculated based on urinary drug excretion. Ae, amount excreted; tmaxrate, time to reach maximum urine excretion rate; t1/2λz, apparent terminal elimination half-life. bCalculated from the individual amount administered dermally and the strength of the cream (∼60 g × 2%). cThe estimated Ae 0-∞ is assumed to closely reflect the percutaneously absorbed triclosan.For all main pharmacokinetic parameters, the intersubject coefficient of variation (CV %) was >30%. This is also in agreement with data in the published literature for oral intake ( 17). This broad variability may be due to individual differences in the rate and extent of transdermal absorption and variations in distribution kinetics, metabolism, and renal clearance of triclosan. Moreover, the number of subjects in this trial was quite small.The safety and tolerability checks (physical examination, electrocardiogram, vital signs, and clinical laboratory assessment) did not provide any evidence for health impairment caused by the study drug. Four mild adverse events occurred; two were located at the skin (irritation on chest after shaving, dry facial skin) and two were probably linked to slight virus infections (running nose, common cold). The good tolerability is consistent with safety and tolerability data on triclosan reported in both published and unpublished studies ( 4, 7).For toxicology assessment, the individual systemic exposure was calculated as the dose absorbed/body weight and compared with the relevant no-observable-adverse-effect level (NOAEL) for triclosan. A NOAEL of 75 mg/kg of body weight was obtained from lifetime studies in hamsters; this species most closely reflects human metabolism and elimination pathways (J. R. Plautz, Ciba Specialty Chemicals, Basel, Switzerland, personal communication, 2007). The amount absorbed after whole-body application was approximately 81 times (range, 41 to 113 times) lower than the NOAEL (Table ). TABLE 3.Toxicology following systemic exposure to triclosan and the calculated safety margin Subject no. | Systemic exposurea (mg/kg) | Safety marginb |
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1 | 1.81 | 41.4 | 2 | 0.82 | 91.1 | 3 | 0.66 | 113.3 | 4 | 1.03 | 72.8 | 5 | 0.70 | 107.2 | 6 | 1.27 | 59.3 | Mean | 1.05 | 80.85 | SD | 0.44 | 28.07 | CV % | 41.6 | 34.7 | Median | 0.93 | 81.97 | Minimum | 0.66 | 41.4 | Maximum | 1.81 | 113.3 | Open in a separate windowaCalculated as the estimated Ae 0-∞/kg of body weight. bCalculated as the NOAEL divided by the estimated systemic exposure, assuming a NOAEL of 75 mg/kg.It can be concluded that the safety margin for therapeutic use of this agent is significantly higher. The recommended adult dose of 2 × 2.5 g of the investigational product would result in a systemic exposure of 0.084 mg/kg, which is approximately 890 times lower than the relevant NOAEL (assuming a body weight of 70 kg and a transdermal fraction absorbed of 5.9%). Hence, this trial did not reveal any toxicological concerns. This is supported by an extensive toxicology database in the literature ( 3, 4, 6, 7).The conclusions regarding the pharmacokinetics and toxicology for triclosan are based on the assumption that the estimated total amount of triclosan excreted via urine, Ae 0-∞, closely reflects the amount absorbed. As our data are based on urinary (not plasma) drug concentrations and could not be compared to those following intravenous administration, it cannot be excluded that the pharmacokinetic results of this study may have been confounded by incomplete renal excretion. After oral intake of triclosan, a mean amount excreted of approximately 50% of the dose is found ( 17), which could reflect accumulation, incomplete absorption and excretion via the feces, or poorly characterized metabolites. All this would result in the “true” amounts absorbed being higher than those calculated in this trial.However, long-term multiple-application studies have shown no accumulation and similar mean area under the time-concentration curve values as those seen following a single-dose application ( 1, 12). In contrast to other species (for example, the rat), excretion of triclosan in humans is predominantly urinary ( 1, 7, 18). Regarding fecal excretion in humans, to our knowledge no data have been published up to now. The extent of a possible contribution of fecal excretion to the elimination of dermally administered triclosan is supposed to be negligible. No oxidative metabolites were detected in the urine in vivo or after absorption through the skin in vitro, and the concentration of triclosan in urine (as the sum of conjugated and unconjugated substance) can be used as a biomarker of exposure to triclosan ( 5). Thus, the chosen study concept was considered suitable for the determination of the percutaneous absorption of triclosan.As shown in Table , the dose absorbed was less than 10% in all individuals (mean, 5.9% of the dose). This corresponds to the absorption of triclosan from dermal spray and soap preparations in humans, which has been reported to be less than 10% of the dose administered ( 12). The in vitro absorption studies with human skin showed a penetration of 6.3% of the dose by 24 h and formation of glucuronide and sulfate metabolites ( 14).Limitations of this study are the small number of participants and the inability to assess the absolute bioavailability based on intravenous data and blood sampling as discussed above. However, the calculated amount absorbed is in agreement with data reported in the literature, and given the large safety margin it can be concluded that triclosan is safe for therapeutic use in dermatological preparations. 相似文献
7.
In vitro double and triple bactericidal activities of doripenem, polymyxin B, and rifampin were assessed against 20 carbapenem-resistant clinical isolates with different mechanisms of carbapenem resistance. Bactericidal activity was achieved in 90% of all bacteria assayed using combinations of polymyxin B, doripenem, and rifampin against five each of the carbapenem-resistant Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Escherichia coli isolates studied. Combinations with these antibacterials may provide a strategy for treatment of patients infected with such organisms.Carbapenem resistance in Acinetobacter baumannii, Pseudomonas aeruginosa, Klebsiella pneumoniae, and Escherichia coli is acknowledged worldwide ( 1, 2, 4, 13, 15, 16). Mechanisms of carbapenem resistance in these bacteria can be due to a variety of carbapenemases alone and/or β-lactamases with porin protein mutations as well as other contributory strategies ( 13, 15). The latest carbapenem approved in the United States, doripenem, has demonstrated in vitro activity against a variety of multidrug-resistant (MDR) Gram-negative organisms, which produce well-characterized β-lactamases, and delayed development of resistance to doripenem has been demonstrated ( 6, 7, 8, 12). Combination therapy with several classes of antibiotics against multidrug-resistant pathogens has revealed increased activity over single agents and delayed development of resistance ( 14). This investigation studied the in vitro bactericidal activities of double and triple antibiotic combinations using doripenem (D), polymyxin B (PB), and rifampin (R) against Acinetobacter baumannii, Pseudomonas aeruginosa, Escherichia coli, and Klebsiella pneumoniae because of their progressive resistance to all available agents.Twenty carbapenem-resistant clinical isolates with different mechanisms of carbapenem resistance and nonrelated by pulsed-field gel electrophoresis were studied, including five imipenem-resistant K. pneumoniae isolates (two with KPC and three with ACT-1 [AMPC-type] β-lactamases), five A. baumannii isolates (non-MBL or KPC β-lactamases), five P. aeruginosa isolates (one KPC and four non-MBL or KPC β-lactamases), and five E. coli isolates (one KPC-3 and four KPC-2 β-lactamases). Susceptibility of the isolates was initially determined by our clinical microbiology laboratory using the Phoenix system, and the results were confirmed in the infectious disease research laboratory using Etest methodology according to the manufacturer''s specifications (bioMérieux North America). E. coli ATCC 25922 was tested as the control strain.Bactericidal experiments were performed using double and triple antibiotic combinations of polymyxin B plus doripenem, polymyxin B plus rifampin, doripenem plus rifampin, and polymyxin B plus doripenem and rifampin as previously described ( 17). Time-kill studies were performed at concentrations at 1/4 of their MICs. Doripenem, polymyxin B, and rifampin alone were also tested at 1/4 MIC against each isolate. For bactericidal assays, samples were taken at time zero and 2, 4, 8, and 24 h. Aliquots were serially diluted, and a 10-μl aliquot was transferred onto plates, spread with a loop to minimize carryover to quantify bacterial counts, and incubated at 35°C for 24 h. Bactericidal activity was defined as a ≥3-log CFU/ml decrease in 24 h.Genotypic and phenotypic characteristics for the carbapenem-resistant isolates used in this study are displayed in Table . All 20 isolates had the following MICs (μg/ml): for rifampin, ranging from 8 to >32; for ertapenem, >32; for doripenem, 1.5 to >32; for imipenem; 6 to >32; for meropenem, 2 to >32; and for polymyxin B, 0.5 to 12. The results of in vitro bactericidal activities and quantitative fold changes with double and triple antibiotic combinations are shown in Table . Combinations of polymyxin B-doripenem-rifampin at 1/4 MICs for each antibiotic were bactericidal for 4/5 K. pneumoniae, 3/5 A. baumannii, 5/5 P. aeruginosa, and 5/5 E. coli isolates. Combinations of polymyxin B-doripenem at 1/4 MICs for each antibiotic were bactericidal for 1/5 K. pneumoniae, 1/5 A. baumannii, 1/5 P. aeruginosa, and 4/5 E. coli isolates. Combinations of polymyxin B-rifampin at 1/4 MICs for each antibiotic were bactericidal for 1/5 K. pneumoniae, 2/5 A. baumannii, 1/5 P. aeruginosa, and 2/5 E. coli isolates. Combinations of doripenem-rifampin at 1/4 MICs for each antibiotic were bactericidal for 2/5 K. pneumoniae, 2/5 A. baumannii, 1/5 P. aeruginosa, and 1/5 E. coli isolates. Bactericidal activity was achieved in 85% of all bacteria assayed using combinations of polymyxin B-doripenem-rifampin, 30% with polymyxin B-doripenem, 30% with doripenem-rifampin, and 25% with polymyxin B-rifampin at 1/4 MICs. Doripenem, polymyxin B, and rifampin tested alone, at 1/4 MIC, were not bactericidal. TABLE 1.Genotypic and phenotypic characteristics for carbapenem-resistant isolates aEtest isolate | Modified Hodge test | MBL Etest | Carbapenem resistance mechanism(s) | MIC (μg/ml)
|
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PB | RI | IP | MP | ERT | D |
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K. pneumoniae 1 | − | − | Porin + ACT-1 | 2 | >32 | >32 | 16 | >32 | 8 | K. pneumoniae 2 | − | − | Porin + ACT-1 | 1 | >32 | >32 | 32 | >32 | 32 | K. pneumoniae 3 | − | − | Porin + ACT-1 | 0.75 | >32 | >32 | 6 | >32 | 6 | K. pneumoniae 4 | + | − | KPC-2 | 1 | >32 | >32 | >32 | >32 | >32 | K. pneumoniae 5 | + | − | KPC-2 | 0.75 | >32 | 32 | 16 | >32 | 24 | A. baumannii 6 | − | − | ND | 1 | 8 | >32 | >32 | >32 | >32 | A. baumannii 7 | − | − | ND | 0.75 | >32 | >32 | >32 | >32 | >32 | A. baumannii 8 | − | − | ND | 1.5 | 16 | >32 | >32 | >32 | >32 | A. baumannii 9 | − | − | ND | 0.5 | 16 | >32 | >32 | >32 | >32 | A. baumannii 10 | − | − | ND | 1 | >32 | >32 | >32 | >32 | >32 | P. aeruginosa 11 | + | − | KPC + PCR | 2 | >32 | >32 | >32 | >32 | >32 | P. aeruginosa 12 | − | − | ND | 12 | >32 | >32 | >32 | >32 | 8 | P. aeruginosa 13 | − | − | ND | 1.5 | >32 | >32 | >32 | >32 | >32 | P. aeruginosa 14 | − | − | ND | 3 | >32 | >32 | >32 | >32 | 32 | P. aeruginosa 15 | − | − | ND | 2 | >32 | >32 | >32 | >32 | >32 | E. coli 16 | + | − | KPC-3 | 0.5 | >32 | >32 | 16 | >32 | 4 | E. coli 17 | + | − | KPC-2 | 1 | >32 | 6 | 3 | >32 | 2 | E. coli 18 | + | − | KPC-2 | 0.5 | >32 | 8 | 2 | 8 | 1.5 | E. coli 19 | + | − | KPC-2 | 1 | >32 | 6 | 2 | >32 | 1.5 | E. coli 20 | + | − | KPC-2 | 0.75 | >32 | 6 | 4 | 16 | 1.5 | Open in a separate windowaPB, polymyxin B; RI, rifampin; IP, imipenem; MP, meropenem; ERT, ertapenem; D, doripenem; ND, not determined; +, positive result; −, negative result. TABLE 2.Logarithmic and fold changes of time-kill experiments at 24 h in various drug combinations with 1/4 MIC aIsolate | PB-D-RI
| PB-D
| PB-RI
| D-RI
|
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LogΔ (CFU/ml) | Fold change | LogΔ (CFU/ml) | Fold change | LogΔ (CFU/ml) | Fold change | LogΔ (CFU/ml) | Fold change |
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K. pneumoniae 1 | ≤−3.70b | ≥5,000 | ≤−3.70b | ≥5,000 | ≤−3.70b | ≥5,000 | ≤−3.70b | ≥5,000 | K. pneumoniae 2 | −2.70 | 500 | −2.10 | 125 | +3.54 | 35,000 | ≤−3.70b | ≥5,000 | K. pneumoniae 3 | ≤−3.70b | ≥5,000 | −0.84 | 7 | −0.65 | 4.4 | +1.51 | 32 | K. pneumoniae 4 | ≤−3.70b | ≥5,000 | +3.79 | 6,100 | +4.30 | 20,000 | +4.30 | 20,000 | K. pneumoniae 5 | ≤−3.70b | ≥5,000 | −2.70 | 500 | +3.45 | 2,793 | +3.07 | 1,188 | A. baumannii 6 | ≤−3.70b | ≥5,000 | +0.19 | 1.5 | ≤−3.70b | ≥5,000 | ≤−3.70b | ≥5,000 | A. baumannii 7 | −2.0 | 100 | +5.3 | 200,000 | +0.87 | 7.4 | +5.30 | 200,000 | A. baumannii 8 | −1.67 | 46 | +0.56 | 3.7 | +2.43 | 267 | ≤−3.70b | ≥5,000 | A. baumannii 9 | ≤−3.70b | ≥5,000 | ≤−3.70b | ≥5,000 | ≤−3.70b | ≥5,000 | +0.8 | 6.3 | A. baumannii 10 | ≤−3.70b | ≥5,000 | +5.05 | 112,000 | +5.30 | 200,000 | +4.0 | 10,000 | P. aeruginosa 11 | ≤−3.70b | ≥5,000 | +1.56 | 36.5 | +2.95 | 886 | +0.52 | 3.3 | P. aeruginosa 12 | ≤−3.70b | ≥5,000 | +4.60 | 39,900 | ≤−3.70b | ≥5,000 | +4.17 | 14,700 | P. aeruginosa 13 | ≤−3.70b | ≥5,000 | ≤−3.70b | ≥5,000 | +4.30 | 20,000 | ≤−3.70b | ≥5,000 | P. aeruginosa 14 | ≤−3.70b | ≥5,000 | +5.30 | 200,000 | +4.30 | 20,000 | +2.66 | 460 | P. aeruginosa 15 | ≤−3.70b | ≥5,000 | +4.75 | 56,000 | +4.30 | 20,000 | +3.93 | 8,600 | E. coli 16 | ≤−3.70b | ≥5,000 | ≤−3.70b | ≥5,000 | −1.81 | 63.8 | +4.32 | 21,100 | E. coli 17 | ≤−3.70b | ≥5,000 | ≤−3.70b | ≥5,000 | ≤−3.70b | ≥5,000 | +5.30 | 200,000 | E. coli 18 | ≤−3.70b | ≥5,000 | ≤−3.70b | ≥5,000 | +2.21 | 161 | +5.03 | 106,000 | E. coli 19 | ≤−3.70b | ≥5,000 | ≤−3.70b | ≥5,000 | ≤−3.70b | ≥5,000 | ≤−3.70b | ≥5,000 | E. coli 20 | ≤−3.70b | ≥5,000 | +0.37 | 2.4 | +1.72 | 53 | +3.56 | 3,633 | Open in a separate windowaPB, polymyxin B; D, doripenem; RI, rifampin. bMaximum log reduction in CFU/ml detectable by assay = (standard inoculum) 5.7 log 10 − (lower limit of detection) 2.0 log 10.Extreme drug resistance (XDR) and pan resistance in Gram-negative bacteria is being reported with increasing frequency ( 5, 10). Although combination therapy has been widely accepted for management of patients infected with Mycobacterium tuberculosis and human immunodeficiency virus, it has not been widely accepted for infections caused by multidrug resistant Gram-negative bacteria. Studies performed in vitro or in animal models often demonstrate synergy with antibiotic combinations, but few translate this success to the clinical arena because of the lack of well-controlled studies ( 3, 9, 11).Our study showed that combinations of polymyxin B-doripenem-rifampin achieved 100% bactericidal activity, defined as a ≥3-log-CFU/ml decrease in 24 h at 1/4 MICs for P. aeruginosa and E. coli, 80% for K. pneumoniae, and 60% for A. baumannii despite resistance to the carbapenems and rifampin alone. A previous study using similar methodology demonstrated that a combination of polymyxin B at 0.5 times the MIC plus rifampin had synergistic activity against 15/16 KPC-producing Klebsiella pneumoniae isolates and synergistic bactericidal activity against 10/16 of the isolates using a combination of polymyxin B plus imipenem ( 2). While in vitro studies do not always correlate with in vivo efficacy, our study showed that bactericidal activity was achieved in 85% of our multidrug resistant isolates at 1/4 their MICs. Administration of approved doses of each of the antibiotics would be in excess of the concentrations used in this in vitro study. In an era of burgeoning multidrug resistance, including that against carbapenems, triple combinations with these antibacterials may provide a strategy for treatment of patients infected with such organisms. 相似文献
8.
The incidence of naturally occurring AmpC β-lactamases with extended activities toward several cephalosporins was evaluated among 17 ceftazidime (CAZ)-resistant Acinetobacter baumannii isolates. Five AmpC β-lactamases (named ADC β-lactamases) were identified, among which those possessing the Val208Ala (inside the omega-loop) or Asn283Ser (helix H-10) substitution conferred higher levels of resistance (4- to 64-fold higher) to CAZ and to cefotaxime in Escherichia coli. This study demonstrates that peculiar AmpCs playing a role in resistance to broad-spectrum cephalosporins in A. baumannii may be identified. Acinetobacter baumannii is commonly associated with serious nosocomial infections ( 4, 10, 14). A growing number of β-lactamases conferring resistance to broad-spectrum cephalosporins in Acinetobacter spp. have been identified. Even though resistance to oxyiminocephalosporins (ceftazidime and cefotaxime) may be related to production of extended-spectrum β-lactamases (ESBLs), it is usually associated with overproduction of an AmpC-type β-lactamase ( 1, 2, 9). Overexpression of the blaAmpC gene of A. baumannii may occur as a result of an insertion sequence, IS Aba1, providing strong promoter sequences ( 5, 8, 13), being located upstream.Most AmpC-type β-lactamases naturally produced by Gram-negative bacteria hydrolyze amino- and ureidopenicillins, cephamycins (cefoxitin and cefotetan), and, at a low level, oxyiminocephalosporins, such as ceftazidime, cefotaxime, and ceftriaxone, and monobactams, such as aztreonam ( 3). AmpCs possessing a broad substrate activity have been reported in Enterobacteriaceae and Pseudomonas aeruginosa ( 11, 12, 16, 19, 20). These AmpCs (or extended-spectrum AmpCs [ESACs]) with activities against several cephalosporins may confer reduced susceptibility to those molecules ( 6, 11, 12, 19). They differ from “regular” cephalosporinases by amino acid substitutions or insertions/deletions in four specific regions that are all located in the vicinity of the active site: the Ω loop, the H-10 helix, the H-2 helix, and the C-terminal extremity of the protein ( 15).Recently, we have identified the first ESAC (named ADC-33, according to the numbering of AmpC β-lactamases from A. baumannii [ 9]) from a single A. baumannii isolate ( 21). ADC-33, possessing a Pro210Arg substitution together with a duplication of an Ala residue at position 215 (inside the Ω loop), hydrolyzed ceftazidime, cefepime, and aztreonam at high levels ( 21).The present study aimed to evaluate the extent of the variability of ADC β-lactamases in A. baumannii. Seventeen nonrepetitive A. baumannii clinical isolates that were recovered in 2007-2008 from patients hospitalized at the Bicêtre Hospital and were resistant to ceftazidime were included in this study. Genotyping was performed by using pulsed-field gel electrophoresis (PFGE) according to the instructions of the manufacturer (Bio-Rad, Marnes-la Coquette, France) as previously described ( 17, 22), and it identified eight distinct clones among the 17 isolates (Table ). TABLE 1.Features of the A. baumannii isolates studied dClone (PFGE) | AmpC overproducerb | ISAba1-blaADC colinearity | ADC variant | OXA-51-like variant | MIC (μg/ml)c
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CAZ | CTX | FEP | CPO | ATM | IPM |
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A (strain CIP)a | − | − | ADC-50 | OXA-64 | 2 | 8 | 1 | 2 | 8 | 0.25 | B (strain AYE) | + | + | ADC-11 | OXA-69 | >256 | >256 | >256 | >256 | >256 | 1 | C | + | + | ADC-51 | OXA-69 | >256 | >256 | 64 | >256 | >256 | >32 | D | + | + | ADC-30 | OXA-66 | 128 | >256 | 32 | 256 | 32 | 4 | E | − | − | ADC-52 | OXA-90 | 32 | 64 | 32 | 64 | 128 | 0.25 | F | + | + | ADC-30 | OXA-66 | 64 | >256 | 32 | 128 | 128 | 2 | G | + | + | ADC-51 | OXA-69 | >256 | >256 | 32 | >256 | >256 | >32 | H | + | + | ADC-30 | OXA-66 | 64 | >256 | 32 | 64 | 128 | 2 | I | + | + | ADC-26 | OXA-69 | 32 | >256 | 16 | 64 | 32 | 2 | J | + | + | ADC-53 | OXA-51 | 64 | >256 | 8 | 32 | 32 | >32 | Open in a separate windowaClones A and B correspond to A. baumannii CIP7010 and A. baumannii AYE, coding for regular AmpC β-lactamases. bAmpC overproduction evaluated by cloxacillin test (250 μg/ml). cCAZ, ceftazidime; CTX, cefotaxime; FEP, cefepime; CPO, cefpirome; ATM, aztreonam; IPM, imipenem. dThere is no IS Aba1- blaOXA-51-like colinearity among any of the clones in the table.In addition to being resistant to ceftazidime, most of the clones were resistant to cefotaxime, ceftriaxone, aztreonam, cefepime, and cefpirome (Table ). By use of cloxacillin-containing plates as described previously ( 17), the susceptibility to ceftazidime was recovered for most of the clones (excluding clones C, E, and G), indicating that overproduction of the ADC β-lactamase was responsible for the resistance to ceftazidime. Double-disk synergy tests using clavulanic acid-containing disks were performed as described previously ( 17) for those isolates belonging to clones C, E, and G, but no ESBL production was detected.Insertion sequence IS Aba1, providing strong promoter sequences (−35 [TTAGAA] and −10 [TTATTT]) immediately upstream of the blaAmpC gene, was identified in almost all clones, similar to previous observations ( 8).Analysis of the naturally occurring carbapenem-hydrolyzing blaOXA-51-like sequences was also performed as described previously (Table ) ( 7, 18). No colinearity between IS Aba1 and the blaOXA-51-like genes was observed in any of these isolates.The blaAmpC genes of the A. baumannii isolates were sequenced and cloned with or without the PISAba1 promoter as described previously ( 21). The inserts containing the PISAba1 promoter were further named with “P+.” The A. baumannii AYE clinical isolate and A. baumannii CIP7010 reference strain were used to clone wild-type blaADC genes expressing ADC-11 and ADC-50, respectively. Five ADC variants (ADC-26, ADC-30, ADC-51, ADC-52, and ADC-53) were identified (Fig. ), with ADC-51, ADC-52, and ADC-53 corresponding to newly identified enzymes. Amino acid changes were not identified either in the SVSK, YSN, and KTG conserved motifs or in helix H-2, previously associated with the extended activity of ESACs identified in other Gram-negative species ( 11, 15). However, substitutions Val208Ala located in the omega loop of ADC-53 and Asn283Ser located in helix H-10 of ADC-51 were identified. Open in a separate windowAmino acid sequence alignment, including ADC-7 taken as a reference sequence as previously published ( 9) and ADC-11 and ADC-50 as wild-type ADCs, together with the newly characterized ADC-26, ADC-30, ADC-51, ADC-52, and ADC-53. Identical amino acids are indicated by dashes. The typical ADC β-lactamase domains (SVSK, YSN, and KTG) are underlined. Helices H-2 and H-10 are boxed in gray. The Ω loop is boxed in gray and double underlined. Differences observed inside the Ω loop and helix H-10 are in bold. The vertical arrow indicates the position of the +1 amino acid (cleavage site for signal peptide). Numbering is according to the sequence of the mature protein. Asterisks indicate ADC β-lactamases possessing ESAC properties.Subsequent cloning showed that MICs of broad-spectrum cephalosporins differed significantly among the recombinant Escherichia coli strains that did not include the strong PISAba1 promoter upstream of the blaADC genes (Table ). Higher MICs of ceftazidime were observed for E. coli TOP10(pADC-30), E. coli TOP10(pADC-51), and E. coli TOP10(pADC-53), producing β-lactamases ADC-30, ADC-51, and ADC-53, respectively. TABLE 2.MICs of β-lactams for E. coli TOP10 strains harboring recombinant plasmids and a TOP10 reference strain β-Lactam(s)a | MIC(μg/ml) for E. coli TOP10 with:
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pADC-26 | pADC-30 | pADC-51 | pADC-52 | pADC-53 | pADC-11 | No plasmid |
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Amoxicillin | >256 | >256 | 32 | 256 | >256 | >256 | 2 | Amoxicillin + CLA | >256 | >256 | 32 | 256 | >256 | 256 | 2 | Ticarcillin | 8 | 8 | 256 | 8 | 16 | 8 | 2 | Ticarcillin + CLA | 8 | 8 | 256 | 8 | 16 | 8 | 2 | Piperacillin | 8 | 8 | 4 | 8 | 16 | 8 | 1 | Piperacillin + TZB | 8 | 8 | 4 | 8 | 16 | 8 | 1 | Cefuroxime | 64 | >256 | 64 | 64 | 32 | 128 | 2 | Ceftazidime | 0.5 | 2 | 32 | 0.5 | 4 | 0.5 | 0.125 | Cefotaxime | 0.25 | 1 | 4 | 0.5 | 2 | 0.5 | 0.06 | Cefepime | 0.03 | 0.03 | 0.06 | 0.03 | 0.03 | 0.032 | 0.03 | Cefpirome | 0.03 | 0.03 | 0.06 | 0.03 | 0.03 | 0.032 | 0.03 | Aztreonam | 0.125 | 0.25 | 0.25 | 0.125 | 0.5 | 0.094 | 0.03 | Imipenem | 0.25 | 0.25 | 0.25 | 0.25 | 0.5 | 0.19 | 0.125 | Meropenem | 0.023 | 0.023 | 0.047 | 0.023 | 0.023 | 0.023 | 0.03 | Open in a separate windowaSusceptibility testing performed by using Etest strips (AB bioMérieux, Solna, Sweden). CLA, clavulanic acid (4 μg/ml); TZB, tazobactam (4 μg/ml).MICs of ceftazidime, cefotaxime, and aztreonam were higher for the clones expressing ADC-30, ADC-51, and ADC-53, suggesting that they might correspond to ESACs (Table ). TABLE 3.MICs of β-lactams for E. coli TOP10 strains harboring recombinant plasmids and a TOP10 reference strain β-Lactam(s)a | MIC(μg/ml) for E. coli TOP10 with:
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pADC-26-P+ | pADC-30-P+ | pADC-51-P+ | pADC-53-P+ | pADC-11-P+ | No plasmid |
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Amoxicillin | >256 | >256 | >256 | >256 | >256 | 2 | Amoxicillin + CLA | >256 | >256 | 256 | >256 | >256 | 2 | Ticarcillin | 128 | 128 | >256 | >256 | 256 | 2 | Ticarcillin + CLA | 128 | 128 | >256 | >256 | 256 | 2 | Piperacillin | >256 | 256 | >256 | >256 | >256 | 1 | Piperacillin + TZB | 256 | 128 | 128 | 256 | 256 | 1 | Cefuroxime | >256 | >256 | >256 | >256 | >256 | 2 | Ceftazidime | 8 | 64 | >256 | 256 | 8 | 0.125 | Cefotaxime | 8 | 64 | >256 | 128 | 8 | 0.06 | Cefepime | 0.125 | 0.25 | 0.5 | 0.25 | 0.125 | 0.03 | Cefpirome | 0.125 | 0.25 | 2 | 0.5 | 0.125 | 0.03 | Aztreonam | 2 | 8 | 8 | 16 | 2 | 0.06 | Imipenem | 0.25 | 0.5 | 0.25 | 0.25 | 0.25 | 0.125 | Meropenem | 0.03 | 0.03 | 0.03 | 0.03 | 0.03 | 0.03 | Open in a separate windowaSusceptibility testing performed by using Etest strips (AB bioMérieux, Solna, Sweden). CLA, clavulanic acid (4 μg/ml); TZB, tazobactam (4 μg/ml).In order to better evaluate the impact of the ADC variants with extended activities (ADC-30, ADC-51, and ADC-53), recombinant plasmids containing the IS Aba1- blaADC fragments were electrotransformed into E. coli HB4 with permeability defects associated with a lack of OmpC and OmpF porins ( 12). Besides that of ceftazidime, the MICs of cefepime, cefpirome, and aztreonam were higher for the ADC-51 producer (16, 64, and 32 μg/ml, respectively) than for the wild-type ADC-26 producer (2, 4, and 8 μg/ml, respectively).Several amino acid substitutions were identified here among ADC β-lactamases (Fig. ). These residues were located at positions 188, 242, 255, 274, 275, and 313 (Fig. ), but none of those was located in domains supposed to be crucial for β-lactamase activity, such as the Ω loop, helix H-2, or helix-H10. A steric view of these substitutions in the overall fold structure of the modeled wild-type ADC-26 variant seems to indicate that these amino acid substitutions are located far from the active site of the enzyme (data not shown). In an analysis of sequences of ADC variants possessing ESAC properties, compared to those of wild-type β-lactamases ADC-11 and ADC-26, it is interesting that both ADC-51 and ADC-53 variants possess a Val208Ala substitution located in the omega loop and an Asn283Ser substitution located in helix H-10, respectively. These substitutions may explain their extended-spectrum activity. However, ADC-30 possesses two specific residues relative to the other ADC sequences (Lys122 and Ser139) and a Thr at position 313 that was identified in the ADC-53 ESAC. Whether those unusual amino acid substitutions (alone or combined) might play a significant role in the broadened activity of ADC-30 remains to be determined.We report here the identification and characterization of five blaADC genes from ceftazidime-resistant A. baumannii isolates. Three of them encode novel ADC variants and three of them possess significant extended activity toward ceftazidime and cefotaxime. After the identification of ESACs in Enterobacteriaceae, the demonstration of their wide diffusion among P. aeruginosa, and the recent and initial finding of such an enzyme in A. baumannii, further investigations are required to evaluate whether ADC β-lactamases with extended activities might be widely distributed in A. baumannii. 相似文献
9.
During 2007-2008, 1,036 Gram-negative bacilli were isolated from patients with complicated intra-abdominal infections in the United States. Against members of the family Enterobacteriaceae, the most active agents in vitro were ertapenem, imipenem, and amikacin, while the least active agent was ampicillin-sulbactam. Ertapenem and imipenem were active against all extended-spectrum-beta-lactamase (ESBL)-positive Escherichia coli. Antimicrobial resistance in Gram-negative bacilli isolated from patients with complicated intra-abdominal infections in the United States continues to increase.In 2003, the Infectious Diseases Society of America published guidelines on the appropriate selection of antimicrobials for the management of patients with complicated intra-abdominal infections (IAIs) ( 14). These guidelines addressed the choice of antimicrobials for both empirical and directed antimicrobial therapy for both community-associated and hospital-associated infections/pathogens. Several surveillance studies and reports have documented the increased levels of antimicrobial resistance to many of the recommended agents with significant awareness of the incidence of extended-spectrum-beta-lactamase (ESBL)-positive Escherichia coli and Klebsiella pneumoniae/oxytoca ( 2, 5, 7, 8, 10). In 2002, the Study for Monitoring Antimicrobial Resistance Trends (SMART) was initiated to monitor yearly the antimicrobial susceptibility of Gram-negative bacilli associated with both community- and hospital-associated IAIs. This report documents the in vitro susceptibility of the most common pathogens associated with IAI in the United States in 2007-2008 to ertapenem, imipenem, and 10 comparator antimicrobial agents.(This work was presented in part as a poster [poster 814] at the 47th Annual Meeting of the Infectious Diseases Society of America, Philadelphia, PA, 29 October to 1 November 2009.)Up to 100 consecutive aerobic or facultative anaerobic Gram-negative bacilli were collected from patients with complicated IAIs from 18 hospital sites in the United States representing all 9 CDC regions in 2007-2008. Antimicrobial susceptibility testing and ESBL detection/confirmation were performed using broth microdilution as previously described ( 5). Reference strains recommended by the Clinical and Laboratory Standards Institute (CLSI) for quality control were utilized, and MICs were interpreted according to CLSI guidelines ( 3). A total of 1,036 isolates were collected in 2007-2008 (Table ). The most commonly isolated pathogens were as follows (percentage of total is shown in parentheses): E. coli (43.1), K. pneumoniae (17.7), Pseudomonas aeruginosa (13.3), Enterobacter cloacae (8.4), Proteus mirabilis (3.0), Klebsiella oxytoca (2.7), Enterobacter aerogenes (2.3), Citrobacter freundii (1.7), and Serratia marcescens (1.5). Overall, members of the family Enterobacteriaceae accounted for 84.7% of all pathogens and 80.4% of the group of pathogens containing only species with greater than 10 isolates represented. Bacteria that were not members of the family Enterobacteriaceae, including P. aeruginosa and Acinetobacter spp., accounted for most of the remaining pathogens. TABLE 1.Susceptibility of IAI pathogens in the United States, 2007-2008 Organism | No. of isolates (% of total) (n = 1,036) | % of isolates susceptible to the following antimicrobiala:
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ETP | IMP | AK | CPE | CFT | CFX | CAZ | CAX | CP | LVX | P/T | A/S |
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C. freundii | 18 (1.7) | 94 | 100 | 100 | 94 | 67 | 17 | 72 | 67 | 72 | 78 | 72 | 61 | E. aerogenes | 24 (2.3) | 100 | 100 | 100 | 100 | 79 | 8 | 63 | 79 | 96 | 96 | 88 | 21 | E. cloacae | 87 (8.4) | 92 | 100 | 99 | 85 | 62 | 1 | 66 | 64 | 85 | 88 | 69 | 17 | E. coli isolates | | | | | | | | | | | | | | All | 447 (43.1) | 99 | 100 | 98 | 97 | 96 | 93 | 96 | 96 | 80 | 81 | 96 | 62 | ESBL-positive | 21 (2.0) | 100 | 100 | 71 | 48* | 38* | 71* | 52* | 38* | 33 | 33 | 62 | 24 | ESBL-negative | 426 (41.1) | 99 | 100 | 100 | 100 | 99 | 94 | 98 | 98 | 82 | 83 | 98 | 64 | K. oxytocab | 28 (2.7) | 100 | 100 | 100 | 96 | 96 | 96 | 96 | 89 | 96 | 100 | 89 | 57 | K. pneumoniae isolates | | | | | | | | | | | | | | All | 183 (17.7) | 96 | 99 | 95 | 91 | 85 | 84 | 86 | 85 | 80 | 84 | 85 | 69 | ESBL-positive | 32 (3.1) | 78 | 94 | 69 | 47* | 19* | 66* | 19* | 19* | 19 | 28 | 28 | 3 | ESBL-negative | 151 (14.6) | 100 | 100 | 100 | 100 | 99 | 87 | 100 | 99 | 93 | 96 | 97 | 83 | P. mirabilisb | 31 (3.0) | 100 | 93 | 100 | 100 | 100 | 100 | 94 | 100 | 97 | 100 | 100 | 97 | P. aeruginosa | 138 (13.3) | NA | 78 | 96 | 72 | 9 | NA | 76 | 17 | 72 | 72 | 83 | NA | S. marcescens | 15 (1.5) | 100 | 100 | 100 | 100 | 100 | 26 | 100 | 100 | 93 | 93 | 100 | 13 | All Enterobacteriaceae with >10 isolatesc | 833 (80.4) | 98 | 99 | 98 | 95 | 89 | 76 | 89 | 89 | 82 | 84 | 90 | 58 | All Enterobacteriaceaed | 878 (84.7) | 98 | 99 | 98 | 95 | 89 | 76 | 89 | 89 | 83 | 85 | 90 | 58 | Other non-Enterobacteriaceaee | 20 (1.9) | NA | 69 | 31 | 23 | 8 | NA | 32 | 15 | 15 | 47 | 23 | 46 | Open in a separate windowaAntimicrobial abbreviations: ETP, ertapenem; IMP, imipenem; AK, amikacin; CPE, cefepime; CFT, cefotaxime; CFX, cefoxitin; CAZ, ceftazidime; CAX, ceftriaxone; CP, ciprofloxacin; LVX, levofloxacin; P/T, piperacillin-tazobactam; A/S, ampicillin-sulbactam. CLSI standard M100-S19 recommends interpreting all cephalosporin results as resistant for ESBL-positive strains ( 3), and these values are indicated with an asterisk. NA, not available because no CLSI breakpoint defined. Numbers in boldface type are susceptibilities that were ≥90%. bIncludes two ESBL-positive strains. cAll members of the family Enterobacteriaceae with more than 10 isolates. dSpecies with <10 isolates are not shown. eOther non- Enterobacteriaceae includes Pasteurella spp. (1 isolate), P. fluorescens (2 isolates), S. maltophilia (6 isolates), and Acinetobacter spp. (11 isolates).Against all members of the family Enterobacteriaceae or members of the Enterobacteriaceae with more than 10 isolates per species in this study, the most active agents (percent susceptible ≥ 90%) included the carbapenems (ertapenem and imipenem), amikacin, cefepime, and piperacillin-tazobactam. Ampicillin-sulbactam was the least active agent, with only 58% of all members of the Enterobacteriaceae susceptible (Table ). E. coli, the most commonly isolated pathogen, was susceptible to most antimicrobials, with only ciprofloxacin, levofloxacin, and ampicillin-sulbactam displaying susceptibilities of <82%. E. coli with an ESBL phenotype exhibited a distinctly higher level of resistance to most antimicrobials overall. The carbapenems (ertapenem and imipenem) retained their activity against ESBL-positive E. coli, while the activity of amikacin, ciprofloxacin, levofloxacin, piperacillin-tazobactam, and ampicillin-sulbactam was considerably diminished. Table shows the percent susceptibility of cephalosporins to ESBL-positive E. coli. However, despite the reported percent susceptibilities, CLSI recommends that for clinical purposes, all cephalosporins should be reported as resistant ( 3). However, in 2010, the CLSI lowered the breakpoints for several extended-spectrum cephalosporins (ceftazidime, ceftriaxone, and cefotaxime) to more accurately reflect the pharmacokinetics/pharmacodynamics of these agents and to better ensure that ESBL-positive E. coli isolates and K. pneumoniae/oxytoca isolates are currently reported as resistant ( 4). Applying the new breakpoints to a global collection of ESBL-positive Enterobacteriaceae resulted in 7%, 31%, and 6% of these isolates susceptible to ceftriaxone, ceftazidime, and cefotaxime, respectively ( 1). Continued confirmation testing of ESBL status may still be required for epidemiologic purposes. K. pneumoniae, the second most commonly isolated pathogen, displayed overall susceptibility of ≥90% for the carbapenems, cefepime, and amikacin. ESBL-positive K. pneumoniae, in comparison to ESBL-positive E. coli, was less susceptible to ertapenem (78% versus 100%), imipenem (94% versus 100%), and ampicillin-sulbactam (3% versus 24%). ESBL production was detected in 4.7% and 17.5% of E. coli and K. pneumoniae isolates, respectively. E. coli and K. pneumoniae/K. oxytoca accounted for 63.5% of all members of the Enterobacteriaceae isolated, indicative of their prevalence in IAI. Of the remaining Enterobacteriaceae isolates, susceptibilities were very similar for C. freundii, E. aerogenes/cloacae, P. mirabilis, and S. marcescens. Each of these species was >90% susceptible to ertapenem, imipenem, and amikacin (Table ). The in vitro activity of ciprofloxacin and levofloxacin varied among the IAI pathogens. Among all members of the Enterobacteriaceae, susceptibility of ≥90% was noted only for E. aerogenes, K. oxytoca, ESBL-negative K. pneumoniae, P. mirabilis, and S. marcescens. Piperacillin-tazobactam activity varied with ESBL phenotype but was consistently lower than ertapenem or imipenem. Amikacin was the only antimicrobial with >90% activity against P. aeruginosa, while 83%, 78%, 76%, and 72% of isolates were susceptible to piperacillin-tazobactam, imipenem, ceftazidime, and ciprofloxacin, respectively.Surveillance studies investigating the susceptibility of pathogens to frequently used IAI antimicrobials have documented the decreased activity of recommended antimicrobials over the past 10 years. However, specific data for the United States describing susceptibility patterns for IAI pathogens from the United States remains limited. In this study, percent susceptibility of recommended IAI antimicrobials, such as imipenem and ciprofloxacin, varied by year (Fig. ). Comparing Enterobacteriaceae and non- Enterobacteriaceae isolates each year from 2002 to 2008 in the United States from the SMART study, the susceptibility to both imipenem and ciprofloxacin vary. Only the decreased in vitro activity of ciprofloxacin versus Enterobacteriaceae reached statistical significance ( P < 0.001) when comparing 2002 to 2008. One focus of global surveillance studies has been to document the increasing incidence of ESBL-producing E. coli and K. pneumoniae/oxytoca ( 6, 11- 13). The global increase in ESBL-positive and fluoroquinolone-resistant Enterobacteriaceae has challenged standard therapeutic treatment regimens. The identification of CTX-M-type ESBLs as predominant in certain areas of the United States from 2000 to 2006 has altered antimicrobial treatment algorithms with decreased susceptibility to fluoroquinolones among CTX-M phenotypes (16%) compared to 36% among SHV or TEM phenotype ( 9). The specific examination of antimicrobial susceptibility among IAI pathogens has been under way since 2002 in the SMART study with the primary goal of monitoring changes in resistance for commonly prescribed antimicrobials used for empirical and directed therapy of Gram-negative bacilli in IAIs. Between 2004 and 2007, studies of global isolates from IAIs in the SMART program demonstrated that the susceptibilities of Gram-negative isolates to the carbapenems have remained stable ( 2, 6, 13), with E. coli and K. pneumoniae isolates, including ESBL-positive isolates, remaining between 98 and 100% susceptible to ertapenem and imipenem. Susceptibility to amikacin has remained high with the percent susceptible continuously over 90 in almost all countries examined ( 6). The emergence of ESBL-positive E. coli and K. pneumoniae, however, has brought with it the reduced activity of fluoroquinolones (ciprofloxacin and levofloxacin) against these phenotypes ( 5). In 2004, >77% of E. coli and >84% of K. pneumoniae of mixed phenotypes were susceptible to both ciprofloxacin and levofloxacin. By 2007, only 17% of ESBL-positive E. coli and 70% of ESBL-negative E. coli remained susceptible to ciprofloxacin ( 5, 13). Similar declines in susceptibility were observed for K. pneumoniae and other species of Enterobacteriaceae ( 5). In the United States, the levels of resistance to recommended antimicrobials for the treatment of IAI infections has not been examined in depth. In 2003, among 378 E. coli isolates collected from patients with IAI in 23 countries, all ESBL-negative isolates were susceptible to both ertapenem and imipenem and >80% of isolates were susceptible to ciprofloxacin. However, in ESBL-positive isolates, 96.2% remained susceptible to ertapenem and 99.1% remained susceptible to imipenem, while only 31% of isolates were susceptible to ciprofloxacin ( 12). Clearly, as the incidence of ESBL-positive E. coli and K. pneumoniae/oxytoca phenotypes increases, surveillance studies continue to document the decreasing activity of recommended IAI antimicrobials with the exception of the carbapenems. Although P. aeruginosa accounts for <10% of all Gram-negative pathogens isolated in IAIs in other studies ( 6), increasing carbapenem, ceftazidime, and fluoroquinolone resistance in this pathogen will continue to complicate empirical antimicrobial therapy. Open in a separate windowSusceptibility of members of the family Enterobacteriaceae and bacteria that were not members of the Enterobacteriaceae to imipenem and ciprofloxacin from 2002 to 2008. The percent susceptibility values from 2002 to 2008 were compared using Fisher''s exact two-tailed test. 相似文献
10.
The in vitro activity of azithromycin against 1,237 nontyphoidal Salmonella enterica isolates collected from Finnish patients between 2003 and 2008 was investigated. Only 24 (1.9%) of the isolates tested and 15 (5.1%) of the 294 isolates with reduced fluoroquinolone susceptibility had azithromycin MICs of ≥32 μg/ml. These data show that azithromycin has good in vitro activity against nontyphoidal S. enterica, and thus, it may be a good candidate for clinical treatment studies of salmonellosis. Salmonella is one of the most common causes of food-borne illnesses and a major cause of human infections all over the world ( 23). Salmonella infections are usually treated with fluoroquinolones or extended-spectrum cephalosporins. Unfortunately, excessive use of fluoroquinolones both in human and in veterinary medicine has led to increasing numbers of resistant isolates, including nontyphoidal strains of Salmonella enterica ( 18, 19, 28). In addition, the nonclassical quinolone resistance phenotype (the Qnr phenotype), showing reduced susceptibility to ciprofloxacin (MIC of ≥0.125 μg/ml) but susceptibility or only low-level resistance to nalidixic acid (MIC of ≤32 μg/ml), has become more common ( 6, 14, 19, 20, 22). Extended-spectrum β-lactamase (ESBL) producers have emerged in Enterobacteriaceae and in Salmonella, and there are reports of the coappearance of ESBL and qnr genes in the same transferable genetic elements ( 5, 10, 21, 27). These resistance problems may jeopardize the treatment of severe Salmonella infections. Thus, alternative antibiotics for the treatment of Salmonella infections are needed. Salmonella isolates are intrinsically resistant to erythromycin via active efflux ( 2) but naturally susceptible to azithromycin ( 29), which is a 15-membered erythromycin derivative. Resistance to macrolides is usually conferred by mutations in nucleotides A2058 and A2059 of the 23S rRNA, according to the Escherichia coli numbering ( 26). Also, the alteration of the 50S ribosomal subunit proteins L4 ( rlpD) and L22 ( rlpV) may lead to macrolide resistance ( 4).The purpose of the present study was to determine the in vitro activity of azithromycin against nontyphoidal Salmonella isolates collected between 2003 and 2008 from Finnish patients. Special attention was paid to isolates with reduced fluoroquinolone susceptibility or showing the Qnr phenotype. In addition, mutations in the 23S rRNA and in the L4 and L22 ribosomal proteins were investigated.(This work was presented in part at the 19th European Congress of Clinical Microbiology and Infectious Diseases [ECCMID], Helsinki, Finland, 2009 [P1043].)A total of 1,237 nontyphoidal Salmonella isolates (638 domestic and 599 foreign) collected from Finnish patients between 2003 and 2008 were included in this study. Starting in January each year, we collected the first 100 domestic and the first 100 foreign, i.e., collected from Finnish travelers returning from abroad, Salmonella isolates. The strains were serotyped at the National Salmonella Reference Centre in Finland.The MICs of antimicrobial agents for the isolates were determined by the agar dilution method according to the CLSI guidelines ( 8). Mueller-Hinton II agar (Becton Dickinson, Cockeysville, MD) was used as the culture medium. All 1,237 Salmonella isolates were tested for susceptibility to ciprofloxacin, nalidixic acid, and azithromycin (all from Sigma, Steinheim, Germany). We tested 809 selected isolates for erythromycin (Sigma) and 635 for telithromycin (Sanofi Aventis, Paris, France) susceptibility. Control strains for susceptibility testing were as described previously ( 14). On the basis of earlier publications ( 1, 16, 17), the MIC breakpoint chosen for reduced ciprofloxacin susceptibility was ≥0.125 μg/ml. For nalidixic acid, CLSI breakpoints were used ( 9). Based on the EUCAST recommendation for S. enterica serovar Typhi ( www.eucast.org) and a previous publication ( 3), the epidemiological cutoff value chosen for azithromycin was ≥32 μg/ml. The susceptibility data were analyzed by using the WHONET 5.4 computer program.Pyrosequencing was used to detect macrolide resistance causing point mutations in the ribosomal target sites A2058 and A2059 ( E. coli numbering) of the 23S rRNA in 22 isolates with azithromycin MICs of ≥32 μg/ml, 44 isolates belonging to the Qnr phenotype, and 73 isolates showing erythromycin MICs of ≥32 μg/ml. Pyrosequencing was performed with previously described primers and protocols ( 15) using a PSQ 96MA pyrosequencer.The 50S ribosomal proteins L4 and L22 were amplified, and mutations were screened in 24 isolates having azithromycin MICs of ≥32 μg/ml, of which 6 were of the Qnr phenotype. In addition, 13 isolates having only erythromycin MICs of ≥32 μg/ml and showing the Qnr phenotype were tested. DNA was prepared as described above. The specific primers used for amplification of the complete L4 and L22 genes rlpD and rlpV were Salm_L4_f (5′-TGAAGGCGTAAGGGGATAGCA-3′) and Salm_L4_r (5′-TCAGCAGA CGTTCTTCACGAA-3′) and Salm_L22_f (5′-GAAATAAGGTAG GAGGAAGAG-3′) and Salm_L22_r (5′-CCATTGCTAGTCTCCAGAGTC-3′). The PCR conditions were as follows: 94°C for 10 min, 94°C for 30 s, 56°C for 30 s, and 72°C for 60 s for 33 cycles. Any L4- or L22-positive results were confirmed by direct sequencing of both strands of amplicons using specific PCR primers as previously described ( 24). Amino acid sequences were then compared with the known rlpD and rlpV genes by a BLAST search through the European Bioinformatics Institute ( http://www.ebi.ac.uk/Tools/blast/).Two different populations of S. enterica were detected regarding the azithromycin MIC distribution. The majority of the isolates had azithromycin MICs of 4 to 8 μg/ml, i.e., representing the wild-type population, whereas a minority of the isolates had MICs of 32 to ≥128 μg/ml, i.e., over the epidemiological cutoff value. Between 2003 and 2008, 24 (1.9%) of the 1,237 isolates had azithromycin MICs of ≥32 μg/ml (Fig. ; Table ). Nine (1.4%) of the 638 domestic isolates and 15 (2.1%) of the 599 foreign isolates had azithromycin MICs over the epidemiological cutoff value. Open in a separate windowHistograms of azithromycin ( n = 1,237), erythromycin ( n = 809), and telithromycin ( n = 635) MICs for S. enterica isolates collected from Finnish travelers between 2003 and 2008. The vertical line represents the resistance breakpoint. TABLE 1.Twenty-four S. enterica isolates showing azithromycin MICs of ≥32 μg/ml Isolate no. | Yr | Strain | Origin | S. enterica serovar | AZMa MIC (μg/ml) | qnr geneb |
---|
1 | 2003 | s2099 | Thailand | Newport | 32 | − | 2 | 2003 | s2018 | Thailand | Stanley | 64 | + | 3 | 2003 | s2021 | Thailand | Rissen | >128 | − | 4 | 2003 | s2085 | Thailand | Stanley | 64 | + | 5 | 2003 | s2086 | Thailand | Stanley | 64 | + | 6 | 2003 | s2181 | Finland | Poona | 32 | − | 7 | 2003 | s2137 | Finland | Typhimurium | 128 | − | 8 | 2003 | s2195 | Finland | Virchow | >128 | − | 9 | 2004 | s2236 | Thailand | Stanley | 32 | + | 10 | 2004 | s2265 | Thailand | Stanley | 128 | + | 11 | 2004 | s2280 | Thailand | Stanley | 64 | + | 12 | 2004 | s2389 | Finland | Typhimurium | 128 | − | 13 | 2004 | s2391 | Finland | Typhimurium | 128 | − | 14 | 2005 | s2439 | Egypt | Blockley | 64 | − | 15 | 2005 | s2477 | Egypt | Bredeney | >128 | − | 16 | 2005 | s2608 | Finland | Blockley | 64 | − | 17 | 2006 | s2635 | Thailand | Emek | 64 | − | 18 | 2006 | s2768 | Finland | Blockley | 128 | − | 19 | 2006 | s2829 | Finland | Saintpaul | 64 | − | 20 | 2007 | s2868 | Malaysia | Stanley | 128 | − | 21 | 2007 | s2948 | Finland | Hvittingfoss | 128 | − | 22 | 2008 | s3141 | Thailand | Rissen | 64 | − | 23 | 2008 | s3082 | Thailand | Typhimurium | 128 | − | 24 | 2008 | s3139 | Thailand | Enteritidis | 128 | − | Open in a separate windowaAZM, azithromycin. b+, present; −, absent.Two hundred ninety-four (23.8%) S. enterica isolates showed reduced fluoroquinolone susceptibility, and 53 (18.0%) of them showed the Qnr phenotype. Among the isolates with reduced fluoroquinolone susceptibility, 4 (5.2%) domestic and 11 (5.1%) foreign isolates had azithromycin MICs of ≥32 μg/ml. Among the Qnr phenotype isolates, six (11.3%) had azithromycin MICs of ≥32 μg/ml (Table ). Azithromycin MICs of ≥32 μg/ml were detected among 12 different serovars, S. enterica serovar Stanley being the most common one, and all isolates with a Qnr phenotype belonged to S. enterica serovar Stanley (Table ).Of the S. enterica isolates tested, 99.6% (806/809) had erythromycin MICs of ≥32 μg/ml. The erythromycin MICs varied between 8 and ≥128 μg/ml, and the vast majority of the isolates had erythromycin MICs of ≥64 μg/ml (Fig. ).No mutations in A2058 or A2059 of the 23S rRNA gene were detected among any of the isolates tested. Sequencing of the 50S ribosomal proteins L4 and L22 revealed G235A and C379T mutations in the rlpD gene and G25A in the rlpV gene, respectively. A Glu79-Lys substitution in the rlpD gene was found in six isolates belonging to three different serovars (Table ). An Arg127-Trp substitution in the rlpD gene was found in three S. enterica serovar Montevideo isolates, which also had an Asp9-Asn substitution outside the coding region (Table ). TABLE 2.Mutations found in the 50S ribosomal proteins L4 and L22 and corresponding MICs S. enterica serovar | Origin | Yr | Mutation in L4 and L22
| MICa
|
---|
rlpD | rlpV | AZM | ERY | TEL | CIP | NAL |
---|
Blockley | Egypt | 2005 | G235A | | 64 | >128 | >128 | 0.5 | >512 | Blockley | Finland | 2005 | G235A | | 64 | >128 | >128 | 0.25 | >512 | Blockley | Finland | 2006 | G235A | | 128 | >128 | >128 | 0.25 | >512 | Saintpaul | Finland | 2006 | G235A | | 64 | >128 | >128 | 0.03 | 16 | Typhimurium | Thailand | 2008 | G235A | | 128 | >128 | >128 | 0.06 | 16 | Typhimurium | Finland | 2004 | G235A | | 128 | 64 | NDb | 0.25 | 512 | Montevideo | Thailand | 2004 | C379T | G25A | 4 | 64 | 32 | 0.5 | 32 | Montevideo | Thailand | 2007 | C379T | G25A | 8 | >128 | 32 | 0.5 | 16 | Montevideo | Thailand | 2008 | C379T | G25A | 8 | >128 | 4 | 0.5 | 16 | Open in a separate windowaAZM, azithromycin; ERY, erythromycin; TEL, telithromycin; CIP, ciprofloxacin; NAL, nalidixic acid. bND, not determined. Salmonella isolates are intrinsically resistant to erythromycin via the AcrAB efflux pump ( 2) but naturally susceptible to azithromycin ( 29). Azithromycin has shown good efficacy in the treatment of patients suffering from typhoid fever ( 7, 12, 13, 25, 30), and there has been speculation that azithromycin could be used for empirical therapy of traveler''s diarrhea ( 11, 31). The present study was performed to determine the in vitro activity of azithromycin toward nontyphoidal Salmonella isolates collected from Finnish patients between 2003 and 2008. Our results show that while nearly all (99.6%) of our S. enterica isolates had erythromycin MICs of ≥32 μg/ml, only 24 isolates had azithromycin MICs of ≥32 μg/ml. Azithromycin showed good in vitro efficacy also against S. enterica isolates with reduced fluoroquinolone susceptibility, although 11.3% of the Qnr phenotype isolates showed azithromycin MICs of ≥32 μg/ml.These data show that azithromycin has good in vitro activity against nontyphoidal S. enterica isolates. Although highly azithromycin-resistant isolates did occur, azithromycin was effective even against the isolates with reduced fluoroquinolone susceptibility, including those showing the Qnr phenotype. Based on these results, azithromycin is a good candidate for clinical treatment studies of salmonellosis. 相似文献
11.
Class D β-lactamase-mediated resistance to β-lactams has been increasingly reported during the last decade. Those enzymes also known as oxacillinases or OXAs are widely distributed among Gram negatives. Genes encoding class D β-lactamases are known to be intrinsic in many Gram-negative rods, including Acinetobacter baumannii and Pseudomonas aeruginosa, but play a minor role in natural resistance phenotypes. The OXAs (ca. 150 variants reported so far) are characterized by an important genetic diversity and a great heterogeneity in terms of β-lactam hydrolysis spectrum. The acquired OXAs possess either a narrow spectrum or an expanded spectrum of hydrolysis, including carbapenems in several instances. Acquired class D β-lactamase genes are mostly associated to class 1 integron or to insertion sequences.Class D β-lactamases, also known as oxacillinases or OXA-type β-lactamases (OXAs), are active-serine-site enzymes like Ambler class A and class C β-lactamases, differing from class A and C enzymes in amino acid structure, whereas class B β-lactamases are metalloenzymes with a Zn 2+ ion(s) in the active site ( 4, 71, 78). Even though class D includes mostly enzymes with higher hydrolysis rates for cloxacillin and oxacillin than for benzylpenicillin (hence the name oxacillinases), not all class D β-lactamases have this characteristic. Most of the class D enzymes belong to group 2d of the Bush functional classification scheme for β-lactamases ( 23). Among the four β-lactamase molecular classes, class D β-lactamases are the most diverse enzymes ( 107). This diversity is observed at both the genetic and biochemical levels, with enzymes possessing either a narrow or expanded spectrum of hydrolysis. In addition, several class D β-lactamases have an expanded spectrum of activity resulting from point mutations.Although many class D β-lactamase genes are embedded into class 1 integrons, recent reports indicated that other specific genetic structures, including insertion sequences and transposons, may be associated with class D β-lactamase genes. Numerous class D β-lactamase genes have been identified as a source of acquired resistance in gram-negative bacteria, but recent studies have shown that class D β-lactamases are also naturally produced in clinically significant pathogens and environmental species ( 107).This review focuses on the diversity and substrate profiles of class D β-lactamases, their sources, and the genetics of acquisition of the corresponding genes. All the class D β-lactamases for which a sequence is available in the GenBank databases are listed in Table . TABLE 1.Features of oxacillinases Namea | Alternate name | OXA group | Type | Original host | A or Nb | Associated mobile element
| Gene GC content (%) | Isoelectric pointd
| GenBank accession no.e | Referencef |
---|
Transposon or insertion sequence | Integronc | Exptl | Theoretical |
---|
OXA-1 | OXA-30 | | Narrow spectrum | E. coli | A | Tn2603 | + | 34.4 | 7.4 | 7.7 | {"type":"entrez-nucleotide","attrs":{"text":"J02967","term_id":"214011892","term_text":"J02967"}}J02967 | 113 | OXA-2 | | OXA-2 | Narrow spectrum | S. Typhimurium | A | | + | 50 | 7.7 | 9.1 | {"type":"entrez-nucleotide","attrs":{"text":"X07260","term_id":"47874","term_text":"X07260"}}X07260 | 97 | OXA-3 | | OXA-2 | Narrow spectrum | K. pneumoniae | A | Tn1411 | + | 50 | 7.1 | 8.1 | {"type":"entrez-nucleotide","attrs":{"text":"L07945","term_id":"784887","term_text":"L07945"}}L07945 | 142 | OXA-4 | OXA-35 | | Narrow spectrum | E. coli | A | Tn1409 | + | | 7.5 | | {"type":"entrez-nucleotide","attrs":{"text":"AY162283","term_id":"38154309","term_text":"AY162283"}}AY162283 | 142 | OXA-5 | | | Narrow spectrum | P. aeruginosa | A | Tn1406 | + | 40.2 | 7.6 | 8.4 | {"type":"entrez-nucleotide","attrs":{"text":"X58272","term_id":"48856","term_text":"X58272"}}X58272 | 32 | OXA-6 | | | Narrow spectrum | P. aeruginosa | A | | | | 7.7 | | | UP | OXA-7 | | OXA-10 | Narrow spectrum | E. coli | A | | + | 40.6 | 7.7 | 9.3 | {"type":"entrez-nucleotide","attrs":{"text":"X75562","term_id":"516188","term_text":"X75562"}}X75562 | 145 | OXA-8 | | | | | | | | | | | | | OXA-9 | | | Narrow spectrum | K. pneumoniae | A | Tn1331 | + | 49.5 | 6.9 | 7.1 | {"type":"entrez-nucleotide","attrs":{"text":"M55547","term_id":"155010","term_text":"M55547"}}M55547 | 155 | LCR-1 | | | Narrow spectrum | P. aeruginosa | A | Tn1412 | − | 52 | 6.5 | 7.1 | {"type":"entrez-nucleotide","attrs":{"text":"X56809","term_id":"48809","term_text":"X56809"}}X56809 | 32 | OXA-10 | | | Narrow spectrum | P. aeruginosa | A | Tn1404 | + | 42.1 | 6.1 | 7.0 | {"type":"entrez-nucleotide","attrs":{"text":"U37105","term_id":"17157971","term_text":"U37105"}}U37105 | 70 | OXA-11 | | OXA-10 | ES-OXA | P. aeruginosa | A | | + | 42 | 6.4 | 6.3 | {"type":"entrez-nucleotide","attrs":{"text":"Z22590","term_id":"296549","term_text":"Z22590"}}Z22590 | 60 | OXA-12 | | | Narrow spectrum | A. jandaei | N | | − | 62.3 | 8.6 | 8.4 | {"type":"entrez-nucleotide","attrs":{"text":"U10251","term_id":"606840","term_text":"U10251"}}U10251 | 139 | AmpS | | | Narrow spectrum | A. hydrophila | N | | − | 63 | 7.9 | 7.1 | {"type":"entrez-nucleotide","attrs":{"text":"X80276","term_id":"1072324","term_text":"X80276"}}X80276 | 165 | OXA-13 | | OXA-10 | Narrow spectrum | P. aeruginosa | A | | + | 41.2 | 8.0 | 8.7 | {"type":"entrez-nucleotide","attrs":{"text":"U59183","term_id":"2393719","term_text":"U59183"}}U59183 | 99 | OXA-14 | | OXA-10 | ES-OXA | P. aeruginosa | A | | + | 42.1 | 6.2 | 6.3 | {"type":"entrez-nucleotide","attrs":{"text":"L38523","term_id":"602481","term_text":"L38523"}}L38523 | 38 | OXA-15 | | OXA-2 | ES-OXA | P. aeruginosa | A | | + | 50 | 8.7 | 9.3 | {"type":"entrez-nucleotide","attrs":{"text":"U63835","term_id":"1488048","term_text":"U63835"}}U63835 | 36 | OXA-16 | | OXA-10 | ES-OXA | P. aeruginosa | A | | + | 42.1 | 6.2 | 6.3 | {"type":"entrez-nucleotide","attrs":{"text":"AF043100","term_id":"2815889","term_text":"AF043100"}}AF043100 | 39 | OXA-17 | | OXA-10 | ES-OXA | P. aeruginosa | A | | + | 42.1 | 6.1 | 7.0 | {"type":"entrez-nucleotide","attrs":{"text":"AF060206","term_id":"3089618","term_text":"AF060206"}}AF060206 | 37 | OXA-18 | | | ES-OXA | P. aeruginosa | A | ISCR19 | − | 61.2 | 5.5 | 5.9 | {"type":"entrez-nucleotide","attrs":{"text":"U85514","term_id":"2149410","term_text":"U85514"}}U85514 | 118 | OXA-19 | | OXA-13 | ES-OXA | P. aeruginosa | A | | + | 41.2 | 7.6 | 8.4 | {"type":"entrez-nucleotide","attrs":{"text":"AF043381","term_id":"4105085","term_text":"AF043381"}}AF043381 | 98 | OXA-20 | | | Narrow spectrum | P. aeruginosa | A | | + | 45.1 | 7.4 | 9.0 | {"type":"entrez-nucleotide","attrs":{"text":"AF024602","term_id":"3220157","term_text":"AF024602"}}AF024602 | 108 | OXA-21 | | OXA-3 | Narrow spectrum | A. baumannii | A | | + | 50.1 | 7.0 | 8.1 | {"type":"entrez-nucleotide","attrs":{"text":"Y10693","term_id":"4581956","term_text":"Y10693"}}Y10693 | 162 | OXA-22 | | | Narrow spectrum | R. pickettii | N | | − | 65.5 | 7.0 | 6.4 | {"type":"entrez-nucleotide","attrs":{"text":"AF064820","term_id":"124431496","term_text":"AF064820"}}AF064820 | 112 | OXA-23 | | | CHDL | A. baumannii | A | Tn2006/Tn2007 | − | 38 | 6.7 | 7.0 | {"type":"entrez-nucleotide","attrs":{"text":"AJ132105","term_id":"6735233","term_text":"AJ132105"}}AJ132105 | 42 | OXA-24 | OXA-40 | | CHDL | A. baumannii | A | | − | 34.4 | 8.6 | 9.0 | {"type":"entrez-nucleotide","attrs":{"text":"AJ239129","term_id":"85057160","term_text":"AJ239129"}}AJ239129 | 19 | OXA-25 | | OXA-40 | CHDL | A. baumannii | A | | − | 34.4 | 8.0 | 8.5 | {"type":"entrez-nucleotide","attrs":{"text":"AF201826","term_id":"11493691","term_text":"AF201826"}}AF201826 | 1 | OXA-26 | | OXA-40 | CHDL | A. baumannii | A | | − | 34.4 | 7.9 | 9.0 | {"type":"entrez-nucleotide","attrs":{"text":"AF201827","term_id":"11493693","term_text":"AF201827"}}AF201827 | 1 | OXA-27 | | OXA-23 | CHDL | A. baumannii | A | | − | 38 | 6.8 | 8.0 | {"type":"entrez-nucleotide","attrs":{"text":"AF201828","term_id":"12060144","term_text":"AF201828"}}AF201828 | 1 | OXA-28 | | OXA-13 | ES-OXA | P. aeruginosa | A | | + | 41.2 | 8.1 | 8.7 | {"type":"entrez-nucleotide","attrs":{"text":"AF231133","term_id":"8118215","term_text":"AF231133"}}AF231133 | 125 | OXA-29 | | | Narrow spectrum | L. gormanii | N | | − | 36.6 | 9.0 | 9.4 | {"type":"entrez-nucleotide","attrs":{"text":"AJ400619","term_id":"13539600","term_text":"AJ400619"}}AJ400619 | 49 | OXA-30 | OXA-1 | | Narrow spectrum | E. coli | A | | + | 34.4 | 7.3 | 6.8 | {"type":"entrez-nucleotide","attrs":{"text":"AF255921","term_id":"8118289","term_text":"AF255921"}}AF255921 | 148 | OXA-31 | | OXA-1 | ES-OXA | P. aeruginosa | A | | + | 34.4 | 7.5 | 6.8 | {"type":"entrez-nucleotide","attrs":{"text":"AF294653","term_id":"14029257","term_text":"AF294653"}}AF294653 | 9 | OXA-32 | | OXA-2 | ES-OXA | P. aeruginosa | A | | + | 50 | 7.7 | 9.0 | {"type":"entrez-nucleotide","attrs":{"text":"AF315351","term_id":"14276839","term_text":"AF315351"}}AF315351 | 124 | OXA-33 | OXA-40 | | CHDL | A. baumannii | A | | − | 34.4 | 8.6 | 9.0 | {"type":"entrez-nucleotide","attrs":{"text":"AY008291","term_id":"10946528","term_text":"AY008291"}}AY008291 | | OXA-34 | | OXA-2 | ES-OXA | P. aeruginosa | A | | + | 50 | | 8.9 | {"type":"entrez-nucleotide","attrs":{"text":"AF350424","term_id":"13194855","term_text":"AF350424"}}AF350424 | UP | OXA-35 | | OXA-10 | ES-OXA | P. aeruginosa | A | | + | 41.2 | 8.0 | 8.7 | {"type":"entrez-nucleotide","attrs":{"text":"AF315786","term_id":"13925892","term_text":"AF315786"}}AF315786 | 8 | OXA-36 | | OXA-2 | ES-OXA | P. aeruginosa | A | | + | 49.4 | | 9.2 | {"type":"entrez-nucleotide","attrs":{"text":"AF300985","term_id":"10946342","term_text":"AF300985"}}AF300985 | UP | OXA-37 | | OXA-20 | Narrow spectrum | A. baumannii | A | | + | 44.8 | 7.4 | 8.9 | {"type":"entrez-nucleotide","attrs":{"text":"AY007784","term_id":"11345443","term_text":"AY007784"}}AY007784 | 109 | OXA-38 | | | | | | | | | | | | | OXA-39 | | | | | | | | | | | | | OXA-40 | | | CHDL | A. baumannii | A | | − | 34.4 | 8.6 | 9.0 | {"type":"entrez-nucleotide","attrs":{"text":"AF509241","term_id":"21070419","term_text":"AF509241"}}AF509241 | 65 | OXA-41 | | | | | | | | | | | | | OXA-42 | | | Narrow spectrum | B. pseudomallei | N | | − | 66.3 | 9.2 | 9.3 | {"type":"entrez-nucleotide","attrs":{"text":"AJ488302","term_id":"21262145","term_text":"AJ488302"}}AJ488302 | 111 | OXA-43 | | | Narrow spectrum | B. pseudomallei | N | | − | 65.9 | 9.2 | 9.3 | {"type":"entrez-nucleotide","attrs":{"text":"AJ488303","term_id":"21262147","term_text":"AJ488303"}}AJ488303 | 111 | OXA-44 | | | | | | | | | | | | | OXA-45 | | | ES-OXA | P. aeruginosa | A | ISCR5 | − | 61.8 | 8.8 | 9.4 | {"type":"entrez-nucleotide","attrs":{"text":"AJ519683","term_id":"32329438","term_text":"AJ519683"}}AJ519683 | 153 | OXA-46 | | | Narrow spectrum | P. aeruginosa | A | | + | 47.1 | 7.8 | 8.7 | {"type":"entrez-nucleotide","attrs":{"text":"AF317511","term_id":"24636971","term_text":"AF317511"}}AF317511 | 57 | OXA-47 | | OXA-1 | Narrow spectrum | K. pneumoniae | A | | + | 34.1 | 7.4 | 6.8 | {"type":"entrez-nucleotide","attrs":{"text":"AY237830","term_id":"37931483","term_text":"AY237830"}}AY237830 | 127 | OXA-48 | | | CHDL | K. pneumoniae | A | Tn1999 | − | 44.5 | 7.2 | 8.0 | {"type":"entrez-nucleotide","attrs":{"text":"AY236073","term_id":"69209772","term_text":"AY236073"}}AY236073 | 127 | OXA-49 | | OXA-23 | CHDL | A. baumannii | A | | − | 38 | | 6.0 | {"type":"entrez-nucleotide","attrs":{"text":"AY288523","term_id":"30961997","term_text":"AY288523"}}AY288523 | UP | OXA-50 | | | Narrow spectrum | P. aeruginosa | N | | − | 64.8 | 8.6 | 9.0 | {"type":"entrez-nucleotide","attrs":{"text":"AY306130","term_id":"34591642","term_text":"AY306130"}}AY306130 | 54 | OXA-51 | OXA-Ab1 | | CHDL | A. baumannii | A | | − | 39.3 | 7.0 | 8.0 | {"type":"entrez-nucleotide","attrs":{"text":"AJ309734","term_id":"56541833","term_text":"AJ309734"}}AJ309734 | 22 | OXA-52 | | | | | | | | | | | | | OXA-53 | | OXA-2 | ES-OXA | S. Agona | A | | + | 50.2 | 6.9 | 7.2 | {"type":"entrez-nucleotide","attrs":{"text":"AY289608","term_id":"31096285","term_text":"AY289608"}}AY289608 | 103 | OXA-54 | | | CHDL | S. oneidensis | N | | − | 46.6 | 6.8 | 6.7 | {"type":"entrez-nucleotide","attrs":{"text":"AY500137","term_id":"40786814","term_text":"AY500137"}}AY500137 | 126 | OXA-55 | | | CHDL | S. algae | N | | − | 53.8 | 8.6 | 8.6 | {"type":"entrez-nucleotide","attrs":{"text":"AY343493","term_id":"37789888","term_text":"AY343493"}}AY343493 | 68 | OXA-56 | | | Narrow spectrum | P. aeruginosa | A | | + | 40.7 | 6.5 | 8.7 | {"type":"entrez-nucleotide","attrs":{"text":"AY445080","term_id":"39932884","term_text":"AY445080"}}AY445080 | 25 | OXA-57 | | | Narrow spectrum | B. pseudomallei | N | | − | 66 | | 9.3 | {"type":"entrez-nucleotide","attrs":{"text":"AJ631966","term_id":"45502118","term_text":"AJ631966"}}AJ631966 | 73 | OXA-58 | | | CHDL | A. baumannii | A | | − | 37.4 | 7.2 | 7.2 | {"type":"entrez-nucleotide","attrs":{"text":"AY665723","term_id":"57869076","term_text":"AY665723"}}AY665723 | 130 | OXA-59 | | | Narrow spectrum | B. pseudomallei | N | | − | 65.9 | | 9.3 | {"type":"entrez-nucleotide","attrs":{"text":"AJ632249","term_id":"45771831","term_text":"AJ632249"}}AJ632249 | 73 | OXA-60 | | | Narrow spectrum | R. pickettii | N | | − | 64.9 | 5.1 | 5.4 | {"type":"entrez-nucleotide","attrs":{"text":"AF525303","term_id":"68137399","term_text":"AF525303"}}AF525303 | 55 | OXA-61 | | | Narrow spectrum | C. jejuni | N | | − | 27.4 | | 9.1 | {"type":"entrez-nucleotide","attrs":{"text":"AY587956","term_id":"46561719","term_text":"AY587956"}}AY587956 | 2 | OXA-62 | | | CHDL | P. pnomenusa | N | | − | 65.3 | >9.0 | 9.5 | {"type":"entrez-nucleotide","attrs":{"text":"AY423074","term_id":"39843362","term_text":"AY423074"}}AY423074 | 144 | OXA-63 | | | Narrow spectrum | B. pilosicoli | N | | − | 24.9 | | 6.0 | {"type":"entrez-nucleotide","attrs":{"text":"AY619003","term_id":"52854082","term_text":"AY619003"}}AY619003 | 94 | OXA-64 | OXA-Ab2 | OXA-51 | CHDL | A. baumannii | N | | − | 39.6 | | 8.0 | {"type":"entrez-nucleotide","attrs":{"text":"AY750907","term_id":"58701167","term_text":"AY750907"}}AY750907 | 21 | OXA-65 | OXA-Ab3 | OXA-51 | CHDL | A. baumannii | N | | − | 39.2 | | 8.8 | {"type":"entrez-nucleotide","attrs":{"text":"AY750908","term_id":"58701169","term_text":"AY750908"}}AY750908 | 21 | OXA-66 | OXA-Ab4 | OXA-51 | CHDL | A. baumannii | N | | − | 39.4 | | 9.0 | {"type":"entrez-nucleotide","attrs":{"text":"AY750909","term_id":"58701171","term_text":"AY750909"}}AY750909 | 21 | OXA-67 | OXA-Ab5 | OXA-51 | CHDL | A. baumannii | N | | − | 39 | | 8.0 | {"type":"entrez-nucleotide","attrs":{"text":"DQ491200","term_id":"95070668","term_text":"DQ491200"}}DQ491200 | UP | OXA-68 | OXA-Ab6 | OXA-51 | CHDL | A. baumannii | N | | − | 39 | | 7.1 | {"type":"entrez-nucleotide","attrs":{"text":"AY750910","term_id":"58701173","term_text":"AY750910"}}AY750910 | 21 | OXA-69 | OXA-Ab7 | OXA-51 | CHDL | A. baumannii | N | | − | 39.3 | 8.4 | 8.6 | {"type":"entrez-nucleotide","attrs":{"text":"AY750911","term_id":"58701175","term_text":"AY750911"}}AY750911 | 66 | OXA-70 | OXA-Ab8 | OXA-51 | CHDL | A. baumannii | N | | − | 39.3 | | 9.0 | {"type":"entrez-nucleotide","attrs":{"text":"AY750912","term_id":"58701177","term_text":"AY750912"}}AY750912 | 21 | OXA-71 | OXA-Ab9 | OXA-51 | CHDL | A. baumannii | N | | − | 39.7 | | 8.0 | {"type":"entrez-nucleotide","attrs":{"text":"AY750913","term_id":"58701179","term_text":"AY750913"}}AY750913 | 21 | OXA-72 | | OXA-40 | CHDL | A. baumannii | A | | − | 36.4 | | 8.8 | {"type":"entrez-nucleotide","attrs":{"text":"EF534256","term_id":"157497430","term_text":"EF534256"}}EF534256 | 166 | OXA-73 | | OXA-23 | CHDL | K. pneumoniae | A | | − | 37.6 | | 8.0 | {"type":"entrez-nucleotide","attrs":{"text":"AY762325","term_id":"56684452","term_text":"AY762325"}}AY762325 | UP | OXA-74 | | OXA-10 | Unknown | P. aeruginosa | A | | − | 41.9 | 6.5 | 7.0 | {"type":"entrez-nucleotide","attrs":{"text":"AJ854182","term_id":"117570984","term_text":"AJ854182"}}AJ854182 | 46 | OXA-75 | OXA-Ab10 | OXA-51 | CHDL | A. baumannii | N | | − | 38.7 | | 8.6 | {"type":"entrez-nucleotide","attrs":{"text":"AY859529","term_id":"57491217","term_text":"AY859529"}}AY859529 | 66 | OXA-76 | OXA-Ab11 | OXA-51 | CHDL | A. baumannii | N | | − | 39.3 | | 9.2 | {"type":"entrez-nucleotide","attrs":{"text":"AY949203","term_id":"61661223","term_text":"AY949203"}}AY949203 | 66 | OXA-77 | OXA-Ab12 | OXA-51 | CHDL | A. baumannii | N | | − | 39.2 | | 8.6 | {"type":"entrez-nucleotide","attrs":{"text":"AY949202","term_id":"61661221","term_text":"AY949202"}}AY949202 | 66 | OXA-78 | OXA-Ab13 | OXA-51 | CHDL | A. baumannii | N | | − | 39.2 | | 8.9 | {"type":"entrez-nucleotide","attrs":{"text":"AY862132","term_id":"58701211","term_text":"AY862132"}}AY862132 | UP | OXA-79 | OXA-Ab14 | OXA-51 | CHDL | A. baumannii | N | | − | 39.5 | | 9.0 | {"type":"entrez-nucleotide","attrs":{"text":"EU019534","term_id":"157779402","term_text":"EU019534"}}EU019534 | 47 | OXA-80 | OXA-Ab15 | OXA-51 | CHDL | A. baumannii | N | | − | 39.3 | | 9.0 | {"type":"entrez-nucleotide","attrs":{"text":"EU019535","term_id":"157779404","term_text":"EU019535"}}EU019535 | 47 | OXA-81 | | | | | | | | | | | | | OXA-82 | OXA-Ab16 | OXA-51 | CHDL | A. baumannii | N | | − | 39.4 | | 9.0 | {"type":"entrez-nucleotide","attrs":{"text":"EU019536","term_id":"157779406","term_text":"EU019536"}}EU019536 | 158 | OXA-83 | OXA-Ab17 | OXA-51 | CHDL | A. baumannii | N | | − | 39.5 | | 9.0 | {"type":"entrez-nucleotide","attrs":{"text":"DQ309277","term_id":"83628253","term_text":"DQ309277"}}DQ309277 | 158 | OXA-84 | OXA-Ab18 | OXA-51 | CHDL | A. baumannii | N | | − | 39.4 | | 9.0 | {"type":"entrez-nucleotide","attrs":{"text":"DQ309276","term_id":"83628251","term_text":"DQ309276"}}DQ309276 | 158 | OXA-85 | | | Narrow spectrum | F. nucleatum | N | | − | 24.6 | 5.3 | 6.1 | {"type":"entrez-nucleotide","attrs":{"text":"AY227054","term_id":"37359439","term_text":"AY227054"}}AY227054 | 164 | OXA-86 | OXA-Ab19 | OXA-51 | CHDL | A. baumannii | N | | − | 38.8 | | 8.0 | {"type":"entrez-nucleotide","attrs":{"text":"DQ149247","term_id":"73622524","term_text":"DQ149247"}}DQ149247 | 159 | OXA-87 | OXA-Ab20 | OXA-51 | CHDL | A. baumannii | N | | − | 38.9 | | 8.0 | {"type":"entrez-nucleotide","attrs":{"text":"DQ348075","term_id":"85812758","term_text":"DQ348075"}}DQ348075 | 159 | OXA-88 | OXA-Ab21 | OXA-51 | CHDL | A. baumannii | N | | − | 39.2 | | 9.2 | {"type":"entrez-nucleotide","attrs":{"text":"DQ392963","term_id":"88697140","term_text":"DQ392963"}}DQ392963 | 75 | OXA-89 | OXA-Ab22 | OXA-51 | CHDL | A. baumannii | N | | − | 38.4 | 7.0 | 8.6 | {"type":"entrez-nucleotide","attrs":{"text":"DQ445683","term_id":"90992729","term_text":"DQ445683"}}DQ445683 | 94 | OXA-90 | OXA-Ab23 | OXA-51 | CHDL | A. baumannii | N | | − | 39.2 | | 8.6 | {"type":"entrez-nucleotide","attrs":{"text":"EU433382","term_id":"167995412","term_text":"EU433382"}}EU433382 | UP | OXA-91 | OXA-Ab24 | OXA-51 | CHDL | A. baumannii | N | | − | 39 | | 8.0 | {"type":"entrez-nucleotide","attrs":{"text":"DQ519083","term_id":"108595589","term_text":"DQ519083"}}DQ519083 | 75 | OXA-92 | OXA-Ab25 | OXA-51 | CHDL | A. baumannii | N | | − | 39.3 | | 8.6 | {"type":"entrez-nucleotide","attrs":{"text":"DQ335566","term_id":"84782428","term_text":"DQ335566"}}DQ335566 | 156 | OXA-93 | OXA-Ab26 | OXA-51 | CHDL | A. baumannii | N | | − | 39.3 | | 8.0 | {"type":"entrez-nucleotide","attrs":{"text":"DQ519087","term_id":"94960148","term_text":"DQ519087"}}DQ519087 | 75 | OXA-94 | OXA-Ab27 | OXA-51 | CHDL | A. baumannii | N | | − | 39.3 | | 8.9 | {"type":"entrez-nucleotide","attrs":{"text":"DQ519088","term_id":"94960150","term_text":"DQ519088"}}DQ519088 | 75 | OXA-95 | OXA-Ab28 | OXA-51 | CHDL | A. baumannii | N | | − | 39.5 | | 8.6 | {"type":"entrez-nucleotide","attrs":{"text":"DQ519089","term_id":"94960152","term_text":"DQ519089"}}DQ519089 | 75 | OXA-96 | | OXA-58 | CHDL | A. baumannii | A | | − | 37.5 | | 7.2 | {"type":"entrez-nucleotide","attrs":{"text":"DQ519090","term_id":"94960154","term_text":"DQ519090"}}DQ519090 | 75 | OXA-97 | | OXA-58 | CHDL | A. baumannii | A | | − | 37.8 | | 7.2 | {"type":"entrez-nucleotide","attrs":{"text":"EF102240","term_id":"132252055","term_text":"EF102240"}}EF102240 | 129 | OXA-98 | OXA-Ab29 | OXA-51 | CHDL | A. baumannii | N | | − | 39.2 | | 8.6 | {"type":"entrez-nucleotide","attrs":{"text":"AM279652","term_id":"190360314","term_text":"AM279652"}}AM279652 | UP | OXA-99 | OXA-Ab30 | OXA-51 | CHDL | A. baumannii | N | | − | 39.4 | | 8.0 | {"type":"entrez-nucleotide","attrs":{"text":"DQ888718","term_id":"114159817","term_text":"DQ888718"}}DQ888718 | UP | OXA-100 | | | | | | | | | | | | | OXA-101 | | OXA-10 | Unknown | C. freundii | A | | + | 40.7 | | 8.8 | {"type":"entrez-nucleotide","attrs":{"text":"AM412777","term_id":"118627599","term_text":"AM412777"}}AM412777 | UP | OXA-102 | | OXA-23 | CHDL | A. radioresistens | N | | − | 38 | | 5.8 | Unknown | 123 | OXA-103 | | OXA-23 | CHDL | A. radioresistens | N | | − | 38 | | 5.8 | Unknown | 123 | OXA-104 | OXA-Ab31 | OXA-51 | CHDL | A. baumannii | N | | − | 39.3 | | 8.6 | {"type":"entrez-nucleotide","attrs":{"text":"EF581285","term_id":"147886440","term_text":"EF581285"}}EF581285 | 47 | OXA-105 | | OXA-23 | CHDL | A. radioresistens | N | | − | 38 | | 7.0 | Unknown | UP | OXA-106 | OXA-Ab32 | OXA-51 | CHDL | A. baumannii | N | | − | 39.3 | | 8.9 | {"type":"entrez-nucleotide","attrs":{"text":"EF650032","term_id":"157285898","term_text":"EF650032"}}EF650032 | 47 | OXA-107 | OXA-Ab33 | OXA-51 | CHDL | A. baumannii | N | | − | 39.3 | | 8.6 | {"type":"entrez-nucleotide","attrs":{"text":"EF650033","term_id":"157285900","term_text":"EF650033"}}EF650033 | 47 | OXA-108 | OXA-Ab34 | OXA-51 | CHDL | A. baumannii | N | | − | 39 | | 8.5 | {"type":"entrez-nucleotide","attrs":{"text":"EF650034","term_id":"157285902","term_text":"EF650034"}}EF650034 | 47 | OXA-109 | OXA-Ab35 | OXA-51 | CHDL | A. baumannii | N | | − | 39.3 | | 9.0 | {"type":"entrez-nucleotide","attrs":{"text":"EF650035","term_id":"157285904","term_text":"EF650035"}}EF650035 | 47 | OXA-110 | OXA-Ab36 | OXA-51 | CHDL | A. baumannii | N | | − | 39.3 | | 8.6 | {"type":"entrez-nucleotide","attrs":{"text":"EF650036","term_id":"157285906","term_text":"EF650036"}}EF650036 | 47 | OXA-111 | OXA-Ab37 | OXA-51 | CHDL | A. baumannii | N | | − | 39.4 | | 7.1 | {"type":"entrez-nucleotide","attrs":{"text":"EF650037","term_id":"157285908","term_text":"EF650037"}}EF650037 | 47 | OXA-112 | OXA-Ab38 | OXA-51 | CHDL | A. baumannii | N | | − | 39.4 | | 8.6 | {"type":"entrez-nucleotide","attrs":{"text":"EF650038","term_id":"157285910","term_text":"EF650038"}}EF650038 | 47 | OXA-113 | OXA-Ab39 | OXA-51 | CHDL | A. baumannii | N | | − | 39.3 | | 8.0 | {"type":"entrez-nucleotide","attrs":{"text":"EF653400","term_id":"158518997","term_text":"EF653400"}}EF653400 | 106 | OXA-114 | | | Narrow spectrum | A. xylosoxidans | N | | − | 70.4 | 8.6 | 9.0 | {"type":"entrez-nucleotide","attrs":{"text":"EU188842","term_id":"160369827","term_text":"EU188842"}}EU188842 | 41 | OXA-115 | OXA-Ab40 | OXA-51 | CHDL | A. baumannii | N | | − | 39.3 | | 9.0 | {"type":"entrez-nucleotide","attrs":{"text":"EU029998","term_id":"154201556","term_text":"EU029998"}}EU029998 | UP | OXA-116 | OXA-Ab41 | OXA-51 | | A. baumannii | N | | − | 39.3 | | 8.6 | {"type":"entrez-nucleotide","attrs":{"text":"EU220744","term_id":"159159998","term_text":"EU220744"}}EU220744 | UP | OXA-117 | OXA-Ab42 | OXA-51 | | A. baumannii | N | | − | 39.2 | | 8.6 | {"type":"entrez-nucleotide","attrs":{"text":"EU220745","term_id":"159160000","term_text":"EU220745"}}EU220745 | UP | OXA-118 | | | Narrow spectrum | B. cepacia | A | | + | 49.3 | | 7.3 | {"type":"entrez-nucleotide","attrs":{"text":"AF371964","term_id":"14164990","term_text":"AF371964"}}AF371964 | 33 | OXA-119 | | | Narrow spectrum | Uncultured bacterium | A | | + | 49.4 | | 6.7 | {"type":"entrez-nucleotide","attrs":{"text":"AY139598","term_id":"24209721","term_text":"AY139598"}}AY139598 | 150 | OXA-120 | | | | | | | | | | | | | OXA-121 | | | | | | | | | | | | | OXA-122 | | | | | | | | | | | | | OXA-123 | | | | | | | | | | | | | OXA-124 | | | | | | | | | | | | | OXA-125 | | | | | | | | | | | | | OXA-126 | | | | | | | | | | | | | OXA-127 | | | | | | | | | | | | | OXA-128 | | OXA-10 | CHDL | A. baumannii | N | | + | 39.1 | | 8.0 | {"type":"entrez-nucleotide","attrs":{"text":"EU375515","term_id":"166012597","term_text":"EU375515"}}EU375515 | 52a | OXA-129 | OXA-Ab43 | OXA-5 | Unknown | S. Bredeney | A | | + | 39.9 | | 9.1 | {"type":"entrez-nucleotide","attrs":{"text":"AM932669","term_id":"165971767","term_text":"AM932669"}}AM932669 | 95 | OXA-130 | OXA-Ab44 | OXA-51 | | A. baumannii | N | | − | 39.1 | | 8.5 | {"type":"entrez-nucleotide","attrs":{"text":"EU547445","term_id":"189214263","term_text":"EU547445"}}EU547445 | UP | OXA-131 | OXA-Ab45 | OXA-51 | | A. baumannii | N | | − | 39.4 | | 9.0 | {"type":"entrez-nucleotide","attrs":{"text":"EU547446","term_id":"189214265","term_text":"EU547446"}}EU547446 | UP | OXA-132 | OXA-Ab46 | OXA-51 | | A. baumannii | N | | − | 39.3 | | 8.0 | {"type":"entrez-nucleotide","attrs":{"text":"EU547447","term_id":"189214267","term_text":"EU547447"}}EU547447 | UP | OXA-133 | | OXA-23 | CHDL | A. radioresistens | N | | − | 39.3 | | 6.1 | {"type":"entrez-nucleotide","attrs":{"text":"EU571228","term_id":"190148187","term_text":"EU571228"}}EU571228 | 123 | OXA-134 | | | CHDL | A. lwoffii | N | | − | 46.2 | | 5.3 | | UP | OXA-135 | | | | | | | | | | | | | OXA-136 | | OXA-63 | Narrow spectrum | B. pilosicoli | N | | − | 25.1 | | 5.3 | {"type":"entrez-nucleotide","attrs":{"text":"EU086830","term_id":"158634575","term_text":"EU086830"}}EU086830 | 96 | OXA-137 | | OXA-63 | Narrow spectrum | B. pilosicoli | N | | − | 24.9 | | 5.7 | {"type":"entrez-nucleotide","attrs":{"text":"EU086834","term_id":"158634583","term_text":"EU086834"}}EU086834 | 96 | OXA-138 | | | | | | | | | | | | | OXA-139 | | | | | | | | | | | | | OXA-140 | | | | | | | | | | | | | OXA-141 | | OXA-2 | ES-OXA | P. aeruginosa | A | | + | 49.9 | | 9.1 | {"type":"entrez-nucleotide","attrs":{"text":"EF552405","term_id":"146261808","term_text":"EF552405"}}EF552405 | UP | OXA-142 | | OXA-10 | ES-OXA | P. aeruginosa | A | | + | 42 | | 6.3 | {"type":"entrez-nucleotide","attrs":{"text":"EU358785","term_id":"166034465","term_text":"EU358785"}}EU358785 | UP | OXA-143 | | | CHDL | A. baumannii | A | | − | 34.4 | | 8.7 | | UP | OXA-144 | | | | | | | | | | | | | OXA-145 | | OXA-10 | ES-OXA | P. aeruginosa | A | | + | 41.1 | | 8.7 | {"type":"entrez-nucleotide","attrs":{"text":"FJ790516","term_id":"225219825","term_text":"FJ790516"}}FJ790516 | UP | OXA-146 | | | | | | | | | | | | | OXA-147 | | OXA-10 | ES-OXA | P. aeruginosa | A | | | 41 | | 8.1 | {"type":"entrez-nucleotide","attrs":{"text":"FJ848783","term_id":"226536681","term_text":"FJ848783"}}FJ848783 | UP | Open in a separate windowaThe nomenclature is in accordance with that provided by G. Jacoby on the Lahey website ( http://www.lahey.org/Studies/other.asp#table1). Lacking variants (in boldface) are those for which a number has been assigned on this website but for which no information is yet available. bA, acquired; N, natural. c+, the oxacillinase gene was found to be associated with an integron-borne gene cassette; −, the gene is not associated with an integron-borne gene cassette. dExperimentally obtained pI values (when available) versus calculated values. Theoretical values were calculated using software found at the ExPASy proteomics tools website ( http://www.expasy.ch/tools/) and the amino acid sequences of the mature proteins only. Peptide cleavage site identification was performed with SignalP ( http://www.cbs.dtu.dk/services/SignalP/), and pI computing was performed with the Compute pI/ Mw tool ( http://www.expasy.ch/tools/pi_tool.html). eUP, unpublished. 相似文献
12.
Infections with multidrug-resistant Acinetobacter baumannii- Acinetobacter calcoaceticus complex bacteria complicate the care of U.S. military personnel and civilians worldwide. One hundred thirty-three isolates from 89 patients at our facility during 2006 and 2007 were tested by disk diffusion, Etest, and broth microdilution for susceptibility to tetracycline, doxycycline, minocycline, and tigecycline. Minocycline was the most active in vitro, with 90% of the isolates tested susceptible. Susceptibilities varied significantly with the testing method. The acquired tetracycline resistance genes tetA, tetB, and tetA(39) were present in the isolates.Multidrug-resistant Acinetobacter baumannii- Acinetobacter calcoaceticus complex bacteria cause infections in traumatic wounds in U.S. military personnel injured in Iraq and Afghanistan ( 9). A previous study of isolates recovered at our facility during 2003 to 2005 found these isolates to be highly susceptible to minocycline ( 6), and our clinical experience with minocycline for the treatment of these infections has been favorable ( 5). The possibility of increasing resistance to minocycline is of concern, as it would further restrict therapeutic options for multidrug-resistant isolates and may necessitate the use of agents with a greater potential for toxicity, such as colistin. Tigecycline has been proposed as a therapeutic option for multidrug-resistant A. baumannii- A. calcoaceticus complex infections (Tygacil package insert, Wyeth Pharmaceuticals, 2005), but its in vitro activity against isolates of military origin is uncertain.The antibiogram for tetracycline, doxycycline, minocycline, and tigecycline was determined by using 133 clinical isolates from blood and wound infections of 89 patients admitted to our facility in 2006 and 2007. Serial isolates were included only when separated by at least 72 h. Susceptibilities to each antimicrobial were determined from a single measurement by disk diffusion (Becton Dickinson, Sparks, MD), Etest (AB Biodisk, Solna, Sweden), and broth microdilution by the methods of the Clinical and Laboratory Standards Institute (CLSI) ( 3). Discordant results were tabulated as very major errors (reported susceptible when resistant), major errors (reported resistant when susceptible), or minor errors (reported intermediate when resistant or susceptible or vice versa). CLSI interpretive criteria were used ( 4), except for tigecycline, for which no interpretive criteria are available.Clonal relationships were assessed by pulsed-field gel electrophoresis (PFGE) with ApaI digestion (Centers for Disease Control and Prevention PulseNet protocols; http://www.cdc.gov/PULSENET/protocols.htm [accessed 25 July 2007]), with modifications for Acinetobacter. Strains were considered to be related if their Dice coefficient was ≥85% (Bionumerics; Applied Maths Inc., Austin, TX). The 89 single-patient isolates were confirmed to be members of the A. baumannii- A. calcoaceticus complex by amplification of blaOXA-51-like β-lactamase genes and by amplified ribosomal DNA restriction analysis (ARDRA) with the restriction enzymes AluI, HinfI, HhaI, RsaI, MboI, and MspI ( 12, 13).The presence of tetracycline resistance genes in 89 single-patient isolates was determined by PCR amplification for the tetA, tetB, tetH, tetL, tetM, tetA(39), and tetA(41) genes with previously published primer sequences by previously described methods ( 1, 8, 11). Data were analyzed according to susceptibility phenotype, PFGE type, and Acinetobacter species as determined by ARDRA.Consistent with our clinical experience and prior laboratory observations, minocycline had the highest in vitro activity, reflected in the MICs for 50 and 90% of the strains tested (MIC 50 and MIC 90, respectively) and the percentage of isolates susceptible according to the broth microdilution method (Table ). The in vitro activities of tetracycline and doxycycline were low. The modal MIC of minocycline was more favorable than that of tigecycline. TABLE 1.Broth microdilution susceptibilities and MIC distribution from 89 single-patient A. baumannii- A. calcoaceticus complex isolates Agent | MIC50 | MIC90 | % Sa | No. of isolates for which MIC (μg/ml) was:
|
---|
≤0.06 | 0.125 | 0.25 | 0.5 | 1 | 2 | 4 | 8 | ≥16 |
---|
Tetracycline | ≥16 | ≥16 | 10.1 | 0 | 0 | 0 | 0 | 1 | 4 | 4 | 4 | 76 | Doxycycline | ≥16 | ≥16 | 31.5 | 4 | 4 | 1 | 1 | 11 | 2 | 5 | 12 | 49 | Minocycline | 1 | 4 | 89.9 | 9 | 0 | 5 | 14 | 35 | 12 | 5 | 6 | 3 | Tigecycline | 4 | 8 | | 0 | 1 | 3 | 2 | 8 | 29 | 9 | 30 | 7 | Open in a separate windowaS, susceptible.The accuracy of the disk diffusion and Etest methods was evaluated by comparing the results of 133 isolates tested by these methods to the reference method of broth microdilution (Table ). Minocycline susceptibility varied widely by testing method, from 36.8% by disk diffusion to 88.7% by broth microdilution. No very major errors were observed. Etest committed fewer major errors than disk diffusion for doxycycline, while the methods were equivalent for minocycline. Etest committed fewer minor errors than disk diffusion for tetracycline and minocycline. There was no predominating type of minor error for either testing method (data not shown). TABLE 2.Rates of susceptibility testing errors among 133 clinical isolates by antimicrobial agent and testing method Agent and testing methoda | % Susceptible | Very major errorb (%) | Major errorc (%) | Minor errord (%) |
---|
Tetracycline | | | | | DD | 1.5 | 0 | 0 | 10.5 | ET | 3.8 | 0 | 0 | 9.0 | BMD | 9.0 | | | | Doxycycline | | | | | DD | 22.6 | 0 | 5.3 | 13.5 | ET | 22.6 | 0 | 3.0 | 18.8 | BMD | 30.1 | | | | Minocycline | | | | | DD | 36.8 | 0 | 1.5 | 53.4 | ET | 69.9 | 0 | 1.5 | 18.0 | BMD | 88.7 | | | | Open in a separate windowaDD, disk diffusion; ET, Etest; BMD, broth microdilution. bVery major error, susceptible by DD or ET when resistant by BMD. cMajor error, resistant by DD or ET when susceptible by BMD. dMinor error, intermediate by DD or ET when susceptible or resistant by BMD or susceptible or resistant by DD or ET when intermediate by BMD.The accuracy of disk diffusion testing for determining minocycline susceptibility was poor. By this method, 51% of the isolates in this study would have been incorrectly reported as nonsusceptible to minocycline. This likely occurred due to clustering of the inhibitory zone diameter at or near the susceptibility breakpoint for minocycline in many isolates. Utilizing the Etest would have incorrectly reported 18% of the isolates as nonsusceptible to minocycline, a considerable improvement over disk diffusion but still exceeding the allowable limits of the CLSI ( 2). High disk diffusion error rates for Acinetobacter have been previously reported for tetracycline ( 10) and tigecycline ( 7).We observed 24 distinct PFGE types among the 89 single-patient isolates. Approximately two-thirds of the isolates were represented by four PFGE types (Table ), composed of A. baumannii, A. calcoaceticus, or isolates that were indistinguishable between these by ARDRA (considered to be A. baumannii- A. calcoaceticus complex isolates). All isolates carried the blaOXA-51-like β-lactamase gene. Three PFGE types comprising 61% of the isolates were associated with a minocycline MIC 90 within the susceptible range. Among these three PFGE types, the percentages of isolates susceptible to tetracycline, doxycycline, and minocycline were 0, 18.5, and 100%, respectively. TABLE 3.MIC 90s and tetracycline resistance gene distribution by phenotype, PFGE type, and species among 89 single-patient A. baumannii- A. calcoaceticus complex isolates Phenotype, PFGE type, or species | n | MIC90 (μg/ml) of:
| No. with resistance gene:
|
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TET | DOX | MIN | TGC | tetA | tetB | tetA(39) |
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MIN-S + DOX-S + TET-S | 9 | 4 | 0.5 | 0.25 | 1 | 0 | 0 | 0 | MIN-S + DOX-S + TET-NS | 19 | ≥16 | 4 | 1 | 4 | 4 | 0 | 1 | MIN-S + DOX-NS + TET-NS | 52 | ≥16 | ≥16 | 2 | ≥16 | 13 | 6 | 33 | MIN-NS + DOX-NS + TET-NS | 9 | ≥16 | ≥16 | ≥16 | 8 | 0 | 9 | 0 | PFGE type 1 (A. baumannii-A. calcoaceticus complex) | 34 | ≥16 | ≥16 | 2 | 8 | 0 | 1 | 32 | PFGE type 2 (A. baumannii) | 14 | ≥16 | 8 | 2 | 2 | 14 | 0 | 0 | PFGE type 3 (A. baumannii) | 6 | ≥16 | 1 | 0.5 | 4 | 0 | 0 | 0 | PFGE type 4 (A. calcoaceticus) | 7 | ≥16 | ≥16 | 8 | 8 | 0 | 7 | 0 | All other PFGE types | 28 | ≥16 | ≥16 | ≥16 | 8 | 3 | 7 | 2 | A. baumannii | 38 | ≥16 | ≥16 | 8 | 4 | 16 | 6 | 1 | A. calcoaceticus | 12 | ≥16 | ≥16 | 8 | 8 | 0 | 7 | 0 | A. baumannii-A. calcoaceticus complex | 39 | ≥16 | ≥16 | 2 | ≥16 | 1 | 2 | 33 | Open in a separate windowaMIN, minocycline; DOX, doxycycline; TET, tetracycline; TGC, tigecycline; S, susceptible; NS, nonsusceptible.The tetracycline resistance determinants tetH, tetL, tetM, and tetA(41) were not found in any isolates. The frequencies of tetA, tetB, and tetA(39) increased with advancing resistance phenotype but were less common in the most resistant phenotype. tetA was predominantly found in PFGE type 2 ( A. baumannii). tetB was found in all species and was more common in the less frequent PFGE types. tetA(39) was abundant in PFGE type 1 ( A. baumannii- A. calcoaceticus complex) isolates retaining susceptibility to minocycline. tetB was found in isolates resistant to all of the agents tested, as well as in isolates retaining susceptibility to minocycline.Multidrug-resistant A. baumannii- A. calcoaceticus complex bacteria remain an important cause of infection around the world. Minocycline is active against isolates of military origin, even when susceptibility to other tetracyclines and tigecycline has been lost. Determining minocycline susceptibility is hampered by important differences in accuracy between susceptibility testing methods, with the disk diffusion method significantly underestimating the proportion of susceptible isolates. Thus, in cases of infection with multidrug-resistant A. baumannii- A. calcoaceticus complex bacteria where minocycline therapy is desirable, it may be prudent to perform broth microdilution testing to obtain the most accurate susceptibility determination. 相似文献
14.
The in vitro activities of DC-159a against seven species of Mycobacterium were compared with moxifloxacin, gatifloxacin, levofloxacin, and rifampin. DC-159a was the most active compound against quinolone-resistant multidrug-resistant M. tuberculosis (MIC 90, 0.5 μg/ml) as well as drug-susceptible isolates (MIC 90, 0.06 μg/ml). The anti-tubercle bacilli activity of DC-159a was 4- to 32-fold more potent than those of currently available quinolones. DC-159a also demonstrated the highest activities against clinically important nontuberculous mycobacteria.To be effective, tuberculosis (TB) treatment with a multidrug regimen must be continued for at least 6 months. This complicated regimen makes TB control difficult because of the long treatment duration, resulting in nonadherence of treatment, the development of multidrug-resistant TB (MDR-TB), and an additional problem of TB and human immunodeficiency virus (HIV) coinfection. Consequently, new anti-TB agents are urgently needed to overcome these problems ( 14).Quinolones such as ofloxacin and levofloxacin are classified and used as second-line drugs for MDR-TB cases because they inhibit the supercoiling action of DNA gyrase, which is different from the target enzymes of first-line drugs; however, their bactericidal activities against Mycobacterium tuberculosis are weak in clinical use ( 15). Currently, moxifloxacin and gatifloxacin, which are 8-methoxy fluoroquinolones, have proven to have more potent activities and may enable the duration of treatment to be shortened. Therefore, combination regimens consisting of new quinolones are expected to improve the treatment of TB ( 3, 11, 13). However, there is a problem of cross-resistance among quinolones caused by the previous usage of old quinolones in the treatment of MDR-TB and other respiratory infections. Thus, the emergence of quinolone-resistant M. tuberculosis is a concern ( 4).DC-159a is a newly synthesized broad-spectrum 8-methoxy fluoroquinolone. This compound has been shown previously to have potent activities against various respiratory pathogens, including quinolone-resistant strains ( 2, 7). The present study was performed to compare the in vitro antimycobacterial activities of DC-159a with three currently available quinolones and also rifampin against M. tuberculosis, including quinolone-resistant MDR (QR-MDR) strains and six species of clinically important nontuberculous mycobacteria (NTM).(This work was presented in part at the 46th Interscience Conference on Antimicrobial Agents and Chemotherapy, San Francisco, CA, September 2006.)Bacterial strains were isolated from Japanese patients between 1997 and 2003. The 32 M. tuberculosis isolates included drug-susceptible isolates ( n = 21) and QR-MDR isolates ( n = 11; levofloxacin MICs, ≥2 μg/ml; rifampin MICs, ≥6 μg/ml; isoniazid MICs, ≥4 μg/ml). The NTM isolates comprised slowly growing mycobacteria, including M. kansasii ( n = 22), M. avium (serovar 4 [ n = 10] and serovar 8 [ n = 23]), and M. intracellulare serovar 16 ( n = 17), and rapidly growing mycobacteria, including M. fortuitum ( n = 10), M. abscessus ( n = 12), and M. chelonae ( n = 10). The bacterial strains were isolated from clinical specimens and cultured in Middlebrook 7H9 broth medium (Difco, MD) supplemented with 10% albumin-dextrose-catalase enrichment and 0.2% glycerol to provide 10 7-CFU/ml stock cultures and stored at −80°C until use.Antimicrobial agents were obtained as pure substances from their manufacturers: DC-159a and levofloxacin (LVX; both from Daiichi-Sankyo Pharmaceuticals Co., Ltd., Tokyo, Japan), moxifloxacin (MXF; Bayer Yakuhin, Ltd., Osaka, Japan), gatifloxacin (GAT; Kyorin Co., Ltd., Tokyo, Japan), rifampin (RIF; Sigma-Aldrich Co., Tokyo, Japan).MICs were determined according to the standard agar dilution method recommended by NCCLS ( 10). A multipoint inoculator (Microplanter; Sakuma Seisakusho, Tokyo, Japan) was used to inoculate approximately 10 4 CFU per 2-μl spot onto Middlebrook 7H10 agar (Difco, MD) supplemented with 10% oleic acid-albumin-dextrose-catalase and 0.5% glycerol. The tested agar plates contained antimicrobial agents ranging from 0.015 to 128 μg/ml in 2-fold dilutions. The inoculated agar plates were incubated at 37°C for 21 days for M. tuberculosis, 14 days for M. avium and M. intracellulare, 7 days for M. kansasii, and 3 days for M. fortuitum and M. abscessus. M. chelonae was incubated at 30°C for 3 days. The MIC was defined as the lowest drug concentration yielding no visible colony formation on the agar surface.Summaries of the in vitro activities of DC-159a against M. tuberculosis and NTM in comparison with those of the other three quinolones and RIF are shown in Tables and , respectively. MICs of currently available quinolones were generally similar to those of previous reports ( 1, 5, 8). DC-159a was the most active compound against M. tuberculosis. The MIC 90 of DC-159a against drug-susceptible M. tuberculosis was 0.06 μg/ml, which was 2-fold lower than that of RIF and 4- to 8-fold lower than those of other tested quinolones. The MIC 90 of DC-159a against QR-MDR M. tuberculosis was 0.5 μg/ml, which was 4- to 32-fold lower than those of other tested quinolones and equal to that of LVX against drug-susceptible M. tuberculosis. TABLE 1.Comparison of MICs of DC-159a with other quinolones and rifampin against M. tuberculosisM. tuberculosis isolate type (n) | Drug | MIC (μg/ml)
|
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Range | 50% | 90% |
---|
Drug susceptible (21) | DC-159a | 0.03-0.125 | 0.06 | 0.06 | | MXF | 0.125-0.5 | 0.25 | 0.25 | | GAT | 0.06-0.25 | 0.125 | 0.25 | | LVX | 0.25-1 | 0.5 | 0.5 | | RIF | ≤0.015-0.25 | 0.06 | 0.125 | QR-MDR (11) | DC-159a | 0.125-0.5 | 0.125 | 0.5 | | MXF | 1-4 | 2 | 4 | | GAT | 0.5-2 | 1 | 2 | | LVX | 2-16 | 8 | 16 | | RIF | 16 to >128 | 128 | >128 | Open in a separate windowTABLE 2.Comparison of MICs of DC-159a with other quinolones and rifampin against nontuberculous mycobacteria Mycobacterium species (no. of isolates) | Drug | MIC (μg/ml)
|
---|
Range | 50% | 90% |
---|
Slowly growing mycobacteria | | | | | M. kansasii (22) | DC-159a | 0.03-0.25 | 0.06 | 0.125 | | MXF | 0.06-1 | 0.125 | 0.25 | | GAT | 0.06-1 | 0.125 | 0.5 | | LVX | 0.25-2 | 0.25 | 1 | | RIF | 0.06-128 | 0.25 | 0.25 | M. avium (33): serovar 4 (10) and serovar 8 (23) | DC-159a | 0.25-8 | 1 | 2 | | MXF | 1-16 | 2 | 4 | | GAT | 1-32 | 2 | 8 | | LVX | 2-64 | 8 | 32 | | RIF | 0.25 to >128 | 32 | 128 | M. intracellulare serovar 16 (17) | DC-159a | 0.25-8 | 1 | 4 | | MXF | 0.5-32 | 2 | 8 | | GAT | 1-32 | 4 | 16 | | LVX | 2-32 | 8 | 32 | | RIF | 0.25-128 | 2 | 32 | Rapidly growing mycobacteria | | | | | M. fortuitum (10) | DC-159a | 0.03-0.25 | 0.125 | 0.25 | | MXF | 0.06-0.5 | 0.125 | 0.25 | | GAT | 0.03-0.25 | 0.125 | 0.25 | | LVX | 0.06-2 | 0.25 | 0.5 | | RIF | 1-128 | 32 | 64 | M. chelonae (10) | DC-159a | 4-16 | 4 | 8 | | MXF | 8-64 | 32 | 32 | | GAT | 4-64 | 16 | 32 | | LVX | 4-128 | 32 | 64 | | RIF | >128 | >128 | >128 | M. abscessus (12) | DC-159a | 4-32 | 8 | 16 | | MXF | 16-128 | 64 | 128 | | GAT | 8-64 | 32 | 64 | | LVX | 16 to >128 | 64 | 128 | | RIF | >128 | >128 | >128 | Open in a separate windowFurthermore, DC-159a inhibited the growth of slowly growing NTM and yielded the lowest MIC 90 among the tested quinolones with M. kansasii (MIC 90, 0.125 μg/ml), M. avium (MIC 90, 2 μg/ml), and M. intracellulare (MIC 90, 4 μg/ml). The MIC 90 of DC-159a against the M. avium- M. intracellulare complex was 2- to 16-fold lower than those of other tested quinolones.In the rapidly growing mycobacteria, it is well known that M. fortuitum is susceptible to quinolones, but M. chelonae and M. abscessus are naturally resistant to quinolones ( 6). DC-159a also showed the same pattern of activity against rapidly growing NTM as the other quinolones. The MIC 90 of DC-159a against M. fortuitum (0.25 μg/ml) was comparable to those of MXF and GAT; however, the MIC 90s of DC-159a against M. chelonae (8 μg/ml) and M. abscessus (16 μg/ml) were 4- to 8-fold lower than those of other tested quinolones.In summary, the order of susceptibility of Mycobacterium species to DC-159a was M. tuberculosis > M. kansasii > M. fortuitum > M. avium > M. intracellulare > M. chelonae > M. abscessus.In this study, we compared the in vitro activities of DC-159a with those of LVX, MXF, GAT, and RIF as reference drugs. DC-159a showed the lowest MICs and the narrowest MIC distribution against M. tuberculosis and NTM isolates for the tested drugs. A good activity of DC-159a against quinolone-resistant strains in other bacteria has been reported previously ( 2, 7). The results of this study also confirmed the characteristic advantage of DC-159a against QR-MDR M. tuberculosis. This finding may be attributed to the high inhibitory activities of DC-159a against the mutant GyrA enzymes in quinolone-resistant M. tuberculosis ( 12). The exact mechanism of DC-159a resistance in M. tuberculosis is under investigation.According to the pharmacokinetic study in a monkey model in which an oral dose of 5 mg/kg of body weight was administered, DC-159a achieved a higher peak concentration ( Cmax; 2.20 μg/ml) and area under the concentration-time curve from 0 to 24 h (AUC 0-24; 16.9 μg·h/ml) than the MIC against M. tuberculosis, showed better pharmacokinetic properties than LVX ( Cmax, 1.68 μg/ml; AUC 0-24, 15.3 μg·h/ml), and lacked interaction with cytochrome P450 3A4 ( 9).For substantiation of DC-159a as a novel agent for TB, MDR-TB, extensively drug-resistant TB, and TB/HIV coinfection cases, further intracellular, pharmacokinetic, drug-drug interaction, and in vivo evaluation studies are essential. DC-159a deserves further study as a promising candidate for a better TB cure, with a focus on the establishment of a 3- to 4-month new standard regimen in the near future. 相似文献
15.
We report the dissemination of a conjugative IncI1 plasmid carrying blaCTX-M-1, conferring resistance to extended-spectrum cephalosporins, in Salmonella enterica isolates from poultry and humans in France from 2003 to 2008. By IncI1 plasmid subtyping, this plasmid was shown to be genetically related to that found in Escherichia coli isolates from healthy poultry in France.Food-producing animals are the primary reservoir of zoonotic pathogens, and the prevalence of resistance to extended-spectrum cephalosporins (ESCs) in Escherichia coli and Salmonella enterica has increased in recent years. In Belgium and France, the emergence of resistance to ESCs, due to extended-spectrum β-lactamases (ESBLs), in E. coli and S. enterica from animal (mainly cattle and poultry) and human origins ( 1, 3, 6, 7, 10, 11, 14, 15, 17) has been reported. Resistance in these bacteria was reported to be conferred mainly by the ESBL genes blaCTX-M-2, blaCTX-M-9, blaCTX-M-15, and blaTEM-52 ( 1, 3, 6, 11, 14, 15, 17). In addition, the occurrence of CTX-M-1 ESBL resistance in E. coli isolates recovered from food animals (cattle, poultry, and swine) in France was recently reported ( 7, 10, 11). The ESBL resistance genes were shown to reside on large conjugative plasmids of the IncI1 or IncHI2 incompatibility group ( 3, 5, 6).Since 2003, a number of S. enterica strains showing resistance to ESCs by production of an ESBL not previously detected in Salmonella in France and with various additional resistances to other antibiotic families have been isolated from poultry ( n = 1) and from humans ( n = 9) in France (Table ). The human isolates consisted of seven serovar Typhimurium (including a monophasic variant) strains, one serovar London strain, and one serovar Newport strain, and the avian isolate was of serovar Llandoff. The purpose of the present study was to identify the ESBL gene and to characterize the plasmid(s) carrying this gene. For this, in addition to other methods, we applied the recently described plasmid multilocus sequence typing method for IncI1 plasmids carrying ESBL genes ( 5). TABLE 1.Characteristics of the Salmonella strains and their transconjugants producing CTX-M-1 used in this study aStrainb | Serovar | PFGE type | Origin | Yr | MIC (μg/ml) of:
| Coresistance markersc | IncI1 pMLSTd | SGI1 |
---|
Cro | Caz |
---|
03-8748 | Newport | NDc | Human | 2003 | >256 | 8 | Su, Tm | | − | 03-8748TC1 | | | | | 256 | 2 | Su, Tm | 3 | | 05-9280 | Typhimurium | XTYM-1 | Human | 2005 | >256 | 32 | Cm, Spt, Str, Su, Tc, Tm | | + | 05-9280TC1 | | | | | >256 | 32 | Su, Tm | 3 | | 06CEB6542SAL | Llandoff | ND | Poultry | 2006 | 64 | 4 | Su, Tc | | − | 06CEB6542SALTC1 | | | | | 8 | 0.5 | Su, Tc | 3 | | 06-6550 | Typhimurium | XTYM-115 | Human | 2006 | 256 | 16 | Su, Tc, Tm | | − | 06-6550TC1 | | | | | 64 | 4 | Su, Tm | 3 | | 07-819 | London | ND | Human | 2007 | >256 | 8 | Su, Tm | | − | 07-819TC1 | | | | | 256 | 4 | Su, Tm | 3 | | 08-843 | Typhimurium | XTYM-1 | Human | 2008 | 256 | 16 | Cm, Spt, Str, Su, Tc, Tm | | + | 08-843TC1 | | | | | 256 | 8 | Su, Tm | 3 | | 08-1537 | Typhimurium | XTYM-117 | Human | 2008 | >256 | 64 | Su, Tm | | − | 08-1537TC1 | | | | | 128 | 8 | Su, Tm | 3 | | 08-1745 | Typhimurium | XTYM-117 | Human | 2008 | >256 | 16 | Su, Tm | | − | 08-2211 | Typhimurium | XTYM-117 | Human | 2008 | 256 | 8 | Su, Tm | | − | 08-2712 | 4,5,12:i:− | XTYM-30 | Human | 2008 | 256 | 16 | Su, Tc, Tm | | − | 08-2712TC1 | | | | | 64 | 8 | Su, Tm | 3 | | Open in a separate windowaAbbreviations: Caz, ceftazidime; Cm, chloramphenicol; Cro, ceftriaxone; Spt, spectinomycine; Str, streptomycin; Su, sulfonamide; Tc, tetracycline; Tm, trimethoprim; ND, not determined. bStrains ending in “TC1” are E. coli transconjugant strains. cAntibiotics other than β-lactams. dIncI1 plasmid multilocus sequence type (pMLST), according to Garcia-Fernandez et al. ( 5), of the CTX-M-1 plasmids extracted from transconjugants.The strains studied are shown in Table . Antibiotic susceptibility testing was done by the disc diffusion method, and MICs of ceftriaxone and ceftazidime were determined by Etest as described previously ( 1, 15, 17). Resistance to ESCs was transferred from all Salmonella strains to E. coli recipient strain J5 (resistant to rifampin) by conjugation as previously described ( 1, 15, 17). Depending on the strain, other resistances were transferred, mostly sulfonamide together with trimethoprim resistance (Table ). The other resistances from multidrug-resistant strains were not transferred by conjugation. The levels of resistance to ESCs, as determined by the MIC, were lower in the transconjugant strains than in the parental strains. However, this was also observed in previous studies ( 3, 15). PCR assays to detect ESBL genes (TEM, SHV, and CTX-M) were performed on parental and transconjugant strains using previously described primers ( 1, 15, 17), and nucleotide sequencing of the amplicons identified the blaCTX-M-1 resistance gene in all strains (Table ). Plasmids extracted from the transconjugants were further characterized by PstI restriction analysis, which showed that they were similar, with a size of 100 kb as determined by S1 nuclease experiments (Fig. and data not shown). Interestingly, the plasmid restriction profile was also similar to that from blaCTX-M-1-carrying plasmids from E. coli isolated from healthy poultry in France (Fig. and data not shown) ( 7) but distinct from blaCTX-M-1-carrying plasmids from E. coli isolates from other animal sources in France (data not shown) ( 11). This suggested a possible common avian origin for this blaCTX-M-1-carrying plasmid. Southern blot hybridization experiments using a blaCTX-M-1 gene probe revealed one PstI fragment of 6 kb in all plasmids, which is the same size as that found in the E. coli plasmid of avian origin (Fig. ). The blaCTX-M-1 gene has been previously reported to be linked to the IS Ecp1 insertion sequence ( 7, 11). PCR performed as described previously ( 11), using a forward primer in the IS Ecp1 gene and a reverse primer in the blaCTX-M-1 gene, was positive for all transconjugant plasmids (data not shown). The link with IS Ecp1 was further confirmed by Southern blotting with an IS Ecp1 probe, which revealed a fragment identical in size to that revealed by the blaCTX-M-1 probe on the PstI-restricted plasmids (Fig. ). Open in a separate windowRestriction analysis (PstI) (A) and Southern blot hybridization with a blaCTX-M-1 probe (B) or with an IS Ecp1 probe (C) of plasmid DNAs isolated from E. coli transconjugants with E. coli isolates from poultry origin in France (lanes 1) and the Salmonella isolates in this study (lanes 2) as parental strains.To better clarify the genetic relatedness of the plasmids, the blaCTX-M-1-positive plasmids were typed by the PCR-based replicon typing as previously described ( 2), demonstrating that they all belong to the IncI1 incompatibility group. IncI1 plasmids were recently observed in E. coli and different serovars of Salmonella isolated in Belgium, France, Germany, Spain, and the United Kingdom and were found to be associated with relevant β-lactamases such as CMY-2, CMY-7, CTX-M-1, CTX-M-15, and TEM-52, suggesting a high prevalence of this kind of plasmid in Europe ( 3, 5, 8, 9, 13). In addition, further characterization using the recently described pMLST method for the characterization of IncI1 plasmids showed that all Salmonella blaCTX-M-1-carrying plasmids in this study were of sequence type 3, as reported for E. coli isolates from poultry in France (data not shown) ( 5). This was also confirmed for the E. coli blaCTX-M-1-carrying control plasmids of poultry origin in this study. Thus, like restriction typing, replicon typing and pMLST indicated a possible common avian origin for the blaCTX-M-1-carrying plasmid emerging in E. coli and Salmonella in France.Among the ESC-resistant Salmonella strains studied, two serovar Typhimurium isolates showed an additional multidrug resistance profile with resistances to chloramphenicol, streptomycin, spectinomycin, sulfonamide, tetracycline, and trimethoprim (Table ). This multidrug resistance profile is characteristic of the Salmonella genomic island 1 (SGI1) antibiotic resistance gene cluster commonly found in the serovar Typhimurium DT104 epidemic clone ( 12). Identification of SGI1 and mapping of its antibiotic resistance gene cluster performed as described previously ( 4) confirmed that the two isolates possessed SGI1, with its classical antibiotic resistance gene cluster consisting of a complex class 1 integron ( 12). This combination of SGI1-mediated multidrug resistance in Salmonella strains associated with ESC resistance has rarely been reported, and further surveillance of such strains is thus warranted ( 3).To assess the genetic diversity of the serovar Typhimurium strains, PulseNet standard pulsed-field gel electrophoresis (PFGE) of XbaI-digested chromosomal DNA was carried out ( 16). These strains showed four different PFGE profiles (Fig. and Table ). The XTYM-1 profile exhibited by both SGI1-carrying isolates is the most prevalent profile for DT104 strains in France ( 16). Open in a separate windowXbaI-PFGE profiles of the S. enterica serovar Typhimurium (and monophasic variant) strains studied. M, XbaI-digested DNA from S. enterica serovar Braenderup strain H9812; lane 1, strain 05-9280; lane 2, strain 06-6550; lane 3, strain 08-843; lane 4, strain 08-1537; lane 5, strain 08-1745; lane 6, strain 08-2211; lane 7, strain 08-2712; lane 8, strain 09-1581 (unrelated to the study).In conclusion, this study showed the spread of an IncI1 plasmid carrying the blaCTX-M-1 gene among S. enterica serovars Llandoff, London, Newport, and Typhimurium of animal and human origin. According to our plasmid analyses, this plasmid is likely the same as that found in E. coli from poultry in France. We thus suspect horizontal transfer events that can contribute to its spread between bacterial populations from animals and humans as well ( 14). The further spread of such plasmids in multidrug-resistant strains carrying SGI1 is of concern. 相似文献
16.
From 2002 to 2008, there was a significant increase in extended-spectrum beta-lactamase (ESBL)-positive Escherichia coli isolates in European intra-abdominal infections, from 4.3% in 2002 to 11.8% in 2008 ( P < 0.001), but not for ESBL-positive Klebsiella pneumoniae isolates (16.4% to 17.9% [ P > 0.05]). Hospital-associated isolates were more common than community-associated isolates, at 14.0% versus 6.5%, respectively, for E. coli ( P < 0.001) and 20.9% versus 5.3%, respectively, for K. pneumoniae ( P < 0.01). Carbapenems were consistently the most active drugs tested.Gram-negative bacilli (GNB) continue to play an important role as a cause of hospital-associated (HA) infections ( 8, 19) and have the leading role in intra-abdominal infections (IAIs) ( 3, 20). Furthermore, reports from the Asia/Pacific region show strikingly high levels of extended-spectrum beta-lactamase (ESBL)-producing isolates of Escherichia coli and Klebsiella pneumoniae and diminished susceptibility to many antimicrobial agents ( 11, 16). Antimicrobial resistance in European GNB has been reported ( 4, 7, 10, 17, 25, 27), but none of these studies focused specifically on IAI pathogens. The Study for Monitoring Antimicrobial Resistance Trends (SMART) monitors the susceptibilities of aerobic GNB from IAIs worldwide. This report describes the frequency of occurrence and antimicrobial susceptibilities of ESBL-producing E. coli and K. pneumoniae isolates in community-associated (CA) and HA IAIs in Europe in 2008 and compares these data with those published previously ( 1, 11, 22).Isolates were derived from intra-abdominal body sites (e.g., appendix, peritoneum, colon, bile, pelvis, and pancreas) and were mostly obtained during surgery, though some paracentesis specimens were also accepted. Isolates were considered to be community associated if they were recovered from a specimen taken less than 48 h after the patient was admitted to the hospital and hospital associated if the specimen was taken 48 or more hours after hospital admission, as described previously ( 11). Isolates were from 37 hospitals in 12 countries (1 in Estonia, 4 in France, 5 in Germany, 2 in Greece, 4 in Italy, 1 in Latvia, 1 in Lithuania, 3 in Portugal, 9 in Spain, 1 in Switzerland, 3 in Turkey, and 3 in the United Kingdom). Isolates were sent to the central laboratory of International Health Management Associates, Inc. (Schaumburg, IL) for confirmation of identification and antimicrobial susceptibility testing. MICs were determined using MicroScan dehydrated broth microdilution panels (Siemens Medical Solutions Diagnostics, West Sacramento, CA), following Clinical and Laboratory Standards Institute (CLSI) and the panel manufacturer''s guidelines ( 5). The MIC interpretive criteria followed guidelines established by the European Committee for Antimicrobial Susceptibility Testing (EUCAST) ( http://www.eucast.org [2009]). Using 2008 CLSI guidelines, E. coli and K. pneumoniae isolates were classified as ESBL producers if there was at least an 8-fold reduction (i.e., three doubling dilutions) of the MIC for ceftazidime or cefotaxime tested in combination with clavulanic acid versus the MIC when tested alone ( 5). Quality control (QC) testing was performed each day of testing using the CLSI QC strains E. coli ATCC 25922, Pseudomonas aeruginosa ATCC 27853, and K. pneumoniae ATCC 700603 (positive ESBL control) ( 6). Fisher''s exact test (two tailed) was used to determine significance, and the modified Wald method was used to calculate 95% confidence intervals.The percentages of isolates from HA or CA infections were 57.9% and 38.5% for E. coli ( P < 0.001) and 70.8% and 23.9% for K. pneumoniae ( P < 0.001), respectively. Another 3.6% of E. coli isolates and 5.3% of K. pneumoniae isolates were from patients without information regarding length of stay at the time of specimen collection. After declining slightly in 2004, 2005, and 2006, the rates of ESBL-positive E. coli isolates rose during the last 2 years of the study, reaching 12.3% in 2007 and 14.0% in 2008 (Table ). The rates of ESBL-positive K. pneumoniae isolates in HA infections were more variable before rising to 20.9% in 2008. ESBL-positive E. coli isolate rates among CA IAIs remained relatively stable, from 4.0% in 2002 to 7.4% in 2007 and 6.5% in 2008. The rate of ESBL-positive K. pneumoniae isolates in CA infections was 5.3% in 2008, lower than the rates observed in 2005, 2006, and 2007 and comparable to that in 2003 (4.4%). However, the generally smaller numbers of ESBL-positive K. pneumoniae isolates led to correspondingly wider 95% confidence intervals. The rates of ESBL-positive E. coli isolates in HA infections ranged from 0% (Lithuania and Switzerland) to 30% (Greece), while those for CA infections ranged from 0% (Latvia and Lithuania) to 24% (Italy) (Table ). The rate of CA ESBL-positive E. coli isolates in most countries was lower than the HA rate. ESBL-positive E. coli isolates were detected in all countries with the exceptions of Lithuania and Switzerland. The rates of ESBL-positive K. pneumoniae isolates in HA IAIs also ranged widely,with the highest rate of 56.0% observed in Italy, followed closely by 50% in both Latvia and Lithuania. The rates of ESBL-positive K. pneumoniae isolates in CA IAIs were 0% in all cases except for Germany and Spain, where the rates were 18.2% and 5.4%, respectively. It is worthwhile noting that the numbers of E. coli and K. pneumoniae isolates in several countries were small, leading to very broad confidence intervals. Furthermore, the number of investigator sites varied from country to country, with several countries having one site while Spain had nine. TABLE 1.Percentages of ESBL-positive E. coli and K. pneumoniae isolates from HA and CA IAIs from 2002 to 2008 in Europe aYr of isolation | E. coli
| K. pneumoniae
|
---|
HA only
| CA only
| HA only
| CA only
|
---|
% ESBL pos | 95% CI | No. of isolates | % ESBL pos | 95% CI | No. of isolates | % ESBL pos | 95% CI | No. of isolates | % ESBL pos | 95% CI | No. of isolates |
---|
2002 | 4.80 | 2.2-9.7 | 146 | 4.00 | 1.9-7.8 | 200 | 28.60 | 15.1-47.2 | 28 | 3.70 | 0-19.8 | 27 | 2003 | 13.70 | 11.1-16.8 | 555 | 5.70 | 3.9-8.3 | 456 | 19.00 | 13.0-27.0 | 121 | 4.40 | 1.0-12.7 | 68 | 2004 | 11.80 | 9.7-14.3 | 754 | 7.00 | 5.1-9.5 | 530 | 13.00 | 8.3-19.8 | 138 | 8.40 | 3.9-16.7 | 83 | 2005 | 8.30 | 6.4-10.7 | 637 | 4.40 | 3.1-6.3 | 680 | 14.90 | 9.8-22.0 | 134 | 10.10 | 5.2-18.3 | 89 | 2006 | 7.60 | 5.8-9.9 | 660 | 5.50 | 4.1-7.4 | 776 | 23.80 | 17.8-30.9 | 160 | 11.00 | 6.4-18.1 | 118 | 2007 | 12.30 | 9.9-15.1 | 604 | 7.40 | 5.7-9.7 | 686 | 16.10 | 10.9-23.0 | 143 | 8.90 | 4.7-15.7 | 113 | 2008 | 14.00 | 11.9-16.5 | 863 | 6.50 | 4.7-8.8 | 574 | 20.90 | 16.1-26.7 | 225 | 5.30 | 1.7-13.2 | 76 | Open in a separate windowapos, positive; 95% CI, 95% confidence interval. TABLE 2.Percentages of HA and CA E. coli and K. pneumoniae isolates identified as ESBL positive in Europe in 2008, by country aCountry | Infection source | E. coli
| K. pneumoniae
|
---|
No. of isolates | % ESBL pos | 95% CI | No. of isolates | % ESBL pos | 95% CI |
---|
Estonia | HA | 0 | | | 0 | | | | CA | 20 | 5.0 | 0-25.4 | 1 | 0.0 | 0-83.3 | France | HA | 73 | 9.6 | 4.4-18.8 | 13 | 7.7 | 0-35.4 | | CA | 122 | 6.6 | 3.2-12.6 | 11 | 0.0 | 0-30.0 | Germany | HA | 103 | 18.5 | 12.1-27.1 | 40 | 17.5 | 8.4-32.3 | | CA | 46 | 6.5 | 1.6-18.2 | 11 | 18.2 | 4.0-48.9 | Greece | HA | 20 | 30.0 | 14.3-52.1 | 21 | 28.6 | 13.6-50.2 | | CA | 7 | 14.3 | 0.5-53.4 | 1 | 0.0 | 0-83.3 | Italy | HA | 138 | 10.9 | 6.6-17.3 | 25 | 56.0 | 37.1-73.4 | | CA | 25 | 24.0 | 11.2-43.8 | 2 | 0.0 | 0-71.0 | Latvia | HA | 22 | 27.3 | 12.9-48.4 | 10 | 50.0 | 23.7-76.3 | | CA | 27 | 0.0 | 0-14.8 | 2 | 0.0 | 0-71.0 | Lithuania | HA | 14 | 0.0 | 0-25.2 | 2 | 50.0 | 9.5-91.0 | | CA | 37 | 0.0 | 0-11.2 | 4 | 0.0 | 0-54.6 | Portugal | HA | 77 | 20.8 | 13.1-31.2 | 28 | 3.6 | 0-19.2 | | CA | 31 | 9.7 | 2.6-25.7 | 2 | 0.0 | 0-71.0 | Spain | HA | 332 | 9.3 | 6.6-13.0 | 60 | 13.3 | 6.7-24.4 | | CA | 227 | 5.7 | 3.3-9.6 | 37 | 5.4 | 0.6-18.6 | Switzerland | HA | 4 | 0.0 | 0-54.6 | 4 | 0.0 | 0-54.6 | | CA | 0 | | | 0 | | | Turkey | HA | 51 | 25.5 | 15.4-39.0 | 15 | 20.0 | 6.3-46.0 | | CA | 3 | 0.0 | 0-61.8 | 0 | | | United Kingdom | HA | 29 | 27.6 | 14.5-44.3 | 7 | 14.3 | 0.5-53.4 | | CA | 29 | 6.9 | 0.1-23.0 | 5 | 0.0 | 0-48.9 | Open in a separate windowapos, positive; 95% CI, 95% confidence interval.Ertapenem and imipenem were the most active agents against ESBL-positive and -negative isolates from both HA and CA origins (Table ). The susceptibilities of HA and CA ESBL-positive isolates were similar. However, for ESBL-negative E. coli isolates, several drugs had significantly lower ( P < 0.05) levels of activity against HA than CA isolates. This result potentially denotes selection processes of patients'' endogenous gut microorganisms during hospitalization or the acquisition of more resistant isolates despite the absence of ESBL production. TABLE 3.Susceptibility rates of E. coli and K. pneumoniae isolates from IAIs by ESBL status and isolate source (HA versus CA) in 2008 in Europe Isolate source | Species and ESBL statusb | No. of isolates | % of isolates that were susceptible toa:
|
---|
Ak | AS | Cpe | Cft | Caz | Cax | Cp | Etp | Imp | Lvx |
---|
HA | E. coli, pos | 121 | 53.7 | 9.1 | 9.9 | 3.3 | 5.8 | 3.3 | 22.3 | 99.2 | 100.0 | 24.8 | CA | E. coli, pos | 37 | 59.5 | 5.4 | 8.1 | 0.0 | 8.1 | 2.7 | 29.7 | 100.0 | 100.0 | 32.4 | | P valuec | | 0.5757 | 0.7342 | 1 | 0.5737 | 0.7001 | 1 | 0.3829 | 1 | 1 | 0.3973 | HA | E. coli, neg | 742 | 97.0 | 44.5 | 97.2 | 95.8 | 94.3 | 95.8 | 78.3 | 98.9 | 99.6 | 79.8 | CA | E. coli, neg | 537 | 98.5 | 53.0 | 98.5 | 98.7 | 97.2 | 98.3 | 85.9 | 99.3 | 99.8 | 87.0 | | P valuec | | 0.0942 | 0.0026 | 0.1297 | 0.0024 | 0.0137 | 0.0137 | 0.0138 | 0.7704 | 0.6435 | 0.0007 | HA | K. pneumoniae, pos | 47 | 66.0 | 6.4 | 10.6 | 6.4 | 0.0 | 4.3 | 29.8 | 83.0 | 89.4 | 40.4 | CA | K. pneumoniae, pos | 4 | 75.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 50.0 | 100.0 | 100.0 | 50.0 | | P valuec | | 1 | 1 | 1 | 1 | 1 | 1 | 0.581 | 1 | 1 | 1 | HA | K. pneumoniae, neg | 178 | 92.7 | 62.9 | 91.6 | 92.1 | 91.0 | 90.5 | 79.2 | 93.3 | 94.9 | 83.2 | CA | K. pneumoniae, neg | 72 | 98.6 | 79.2 | 98.6 | 100.0 | 98.6 | 98.6 | 94.4 | 100.0 | 100.0 | 97.2 | | P valuec | | 0.0738 | 0.0166 | 0.0451 | 0.0123 | 0.0283 | 0.0279 | 0.0024 | 0.0212 | 0.063 | 0.0015 | Open in a separate windowaSusceptibility was determined using EUCAST criteria ( http://www.eucast.org [2009]). Ak, amikacin; AS, ampicillin-sulbactam; Cpe, cefepime; Cft, cefotaxime; Caz, ceftazidime; Cax, ceftriaxone; Cp, ciprofloxacin; Etp, ertapenem; Imp, imipenem; Lvx, levofloxacin. bpos, positive; neg, negative. cP values in boldface are significant (<0.05).The low number of ESBL-positive K. pneumoniae isolates collected from HA and CA infections in 2008 (47 and 4, respectively) makes comparison of susceptibility data difficult, and in fact, differences as high as 20.2% failed to achieve statistical significance (Table ). Comparisons of the activities of the study agents against HA and CA ESBL-negative K. pneumoniae isolates revealed significant differences ( P < 0.05) for all agents, with the exceptions of imipenem ( P = 0.063) and amikacin ( P = 0.0738), which were within the group of most active agents (Table ).Various reports have described increases in the incidence of ESBL-positive E. coli and, to a lesser extent, ESBL-positive K. pneumoniae in Europe, particularly in the community compared to the incidence in health care facilities ( 4, 7, 9, 18). Many of these reports were single-year “snapshots” or presented multiyear analyses ending in 2006 or earlier and comprised isolates from different types of infections. In contrast, SMART has been on-going since 2002, collecting data exclusively on hospital-associated and community-associated IAIs.Some investigators have reported dramatic increases in the incidence of E. coli isolates possessing CTX-M ESBLs in the community ( 4, 7, 18, 21). In addition, Ben-Ami et al. ( 2) and Pitout et al. ( 21) reported that isolates producing CTX-M beta-lactamases were significantly more resistant to fluoroquinolones than were isolates producing other types of ESBLs. Although the specific enzyme types of ESBL producers were not identified as part of the SMART program in 2008, a high percentage of fluoroquinolone resistance was observed, denoting the potential presence of these enzymes.In the study reported by Ben-Ami et al. ( 2), the investigators evaluated risk factors for nonhospitalized patients to be infected with an ESBL-positive isolate. These included recent use of antimicrobials, residence in a long-term care facility, recent hospitalization, age of ≥65 years, and male gender. However, 34% of the ESBL isolates in their analysis came from patients with no recent health care contact. Nevertheless, increases of fecal carriage of ESBL-producing isolates in both hospitalized and nonhospitalized patients have been reported ( 24), which may increase the risk for IAI due to these organisms. It is essential for physicians to be aware of the extent of increasing ESBL rates in both species and of the subsequent reduced susceptibilities that these species exhibit to most agents. Based on the results of the present study, the number of options for empirical therapy of IAI in various parts of Europe exhibiting high ESBL-positive rates may therefore be decreasing, particularly for cephalosporins, fluoroquinolones, and ampicillin-sulbactam. However, a limitation of the current study is that the number of investigator sites in some countries was not balanced to correlate with population differences; therefore, more extensive investigations in some of the countries studied are warranted in order to solidify general conclusions and trends.Although the carbapenems were consistently the most active agents in this study, the emergence of carbapenemases in isolates with or without the coproduction of an ESBL ( 7, 13, 15, 23, 24, 26) reinforces the need for continuous local and global monitoring of carbapenem susceptibility. 相似文献
17.
AFN-1252, a potent inhibitor of enoyl-acyl carrier protein reductase (FabI), inhibited all clinical isolates of Staphylococcus aureus ( n = 502) and Staphylococcus epidermidis ( n = 51) tested, including methicillin (meticillin)-resistant isolates, at concentrations of ≤0.12 μg/ml. In contrast, AFN-1252 was inactive (MIC 90, >4 μg/ml) against clinical isolates of Streptococcus pneumoniae, beta-hemolytic streptococci, Enterococcus spp., Enterobacteriaceae, nonfermentative gram-negative bacilli, and Moraxella catarrhalis. These data support the continued development of AFN-1252 for the treatment of patients with resistant staphylococcal infections.AFN-1252 is an investigational inhibitor of staphylococcal FabI, an essential enzyme that catalyzes the reduction of trans-2-enoyl-acyl carrier protein ( trans-2-enoyl-ACP) to acyl-ACP, the final step in each elongation cycle of bacterial fatty acid biosynthesis ( 1, 7, 10). Enoyl-ACP reductase is known to have four distinct enzyme forms: FabI, FabK, FabL, and FabV ( 8). FabI is the sole form of enoyl-ACP reductase present in Staphylococcus aureus, Staphylococcus epidermidis, and a few other bacterial species ( 6, 8, 9). No alternative enzyme or rescue pathway for FabI in staphylococci has been identified, suggesting that FabI is essential to Staphylococcus cell viability and that resistance to FabI inhibitors such as AFN-1252 will not readily emerge with therapy ( 1).AFN-1252 is being developed by Affinium Pharmaceuticals, Inc. (Toronto, Canada), in both oral and intravenous formulations, for the treatment of antimicrobial-susceptible and -resistant staphylococcal infections, particularly infections caused by S. aureus. The structure of AFN-1252 has been described previously ( 9). AFN-1252 has demonstrated in vivo efficacy in a murine subcutaneous abscess model using a strain of methicillin (meticillin)-resistant S. aureus ( 12). The present study was undertaken to assess the in vitro activities of AFN-1252 against recent clinical isolates of staphylococci, as well as other gram-positive cocci and gram-negative bacilli, to demonstrate the full antibacterial spectrum of activity of AFN-1252.Clinically relevant isolates were collected at 12 Canadian hospital laboratories from January to December 2007 as a part of the ongoing CANWARD in vitro surveillance study and shipped to the coordinating laboratory (Health Sciences Centre, Winnipeg, Canada) for identity confirmation and antimicrobial susceptibility testing. Multidrug-resistant staphylococci were defined as those isolates that were resistant to two or more of the agents ciprofloxacin, clindamycin, and gentamicin and included both methicillin-susceptible and methicillin-resistant isolates. Vancomycin-intermediate S. aureus and vancomycin-resistant S. aureus isolates were obtained through the Network on Antimicrobial Resistance in Staphylococcus aureus program (supported under NIAID, NIH, contract no. N01-AI-95359) for testing against AFN-1252.Clinical and Laboratory Standards Institute (CLSI)-specified broth microdilution testing was performed using frozen, in-house-prepared, 96-well panels containing AFN-1252 and comparative agents ( 3). Dimethyl sulfoxide was used as the solvent and diluent for AFN-1252. AFN-1252 was tested over a doubling-dilution concentration range of 0.008 to 4 μg/ml, and its MICs were recorded following 20 to 24 h of incubation at 35°C in ambient air. MICs were interpreted using CLSI M100-S17 guidelines ( 2). For the reference strain S. aureus ATCC 29213, AFN-1252 reproducibly demonstrated an MIC of 0.015 μg/ml.AFN-1252 inhibited all isolates of methicillin-susceptible and methicillin-resistant S. aureus and S. epidermidis at concentrations of ≤0.12 μg/ml (Table ). AFN-1252 demonstrated MIC 90s for methicillin-resistant S. aureus and S. epidermidis and multidrug-resistant S. aureus and S. epidermidis (data not shown) of ≤0.008 μg/ml. AFN-1252 was less active in vitro against vancomycin-intermediate S. aureus isolates ( n = 12; MIC 90, 0.12 μg/ml) and vancomycin-resistant S. aureus isolates ( n = 12; MIC 90, 0.06 μg/ml) than against vancomycin-susceptible isolates (MIC 90, ≤0.008 μg/ml) (data not shown). AFN-1252 was inactive (MIC range, 4 to >4 μg/ml) against nonstaphylococcal gram-positive pathogens and gram-negative pathogens (Table ). TABLE 1.Activities of AFN-1252 and comparator agents against staphylococci, nonstaphylococcal gram-positive pathogens, and gram-negative pathogens Species or isolate group (no. of isolates) | Agent | MIC (μg/ml)
| % of isolates classified by MIC as:
|
---|
50% | 90% | Range | Susceptible | Intermediate | Resistant |
---|
Methicillin-susceptible S. aureus (375) | AFN-1252 | ≤0.008 | ≤0.008 | ≤0.008-0.12 | | | | | Cefazolin | ≤0.5 | 1 | ≤0.5-8 | 100 | 0 | 0 | | Ciprofloxacin | 0.5 | 8 | ≤0.06->16 | 83.8 | 4.2 | 12.0 | | Clindamycin | ≤0.12 | ≤0.12 | ≤0.12->8 | 91.0 | 0.4 | 8.6 | | Gentamicin | ≤0.5 | 1 | ≤0.5->32 | 96.7 | 0.1 | 3.2 | | Linezolid | 2 | 2 | ≤0.12-4 | 100 | 0 | 0 | | Trimethoprim-sulfamethoxazole | ≤0.12 | ≤0.12 | ≤0.12->8 | 99.3 | | 0.7 | | Vancomycin | 1 | 1 | ≤0.25-2 | 100 | 0 | 0 | Methicillin-resistant S. aureus (127) | AFN-1252 | ≤0.008 | ≤0.008 | ≤0.008-0.06 | | | | | Cefazolin | 64 | >128 | 32->128 | 0 | 0 | 100 | | Ciprofloxacin | >16 | >16 | 0.25->16 | 10.1 | 0.3 | 89.6 | | Clindamycin | >8 | >8 | ≤0.12->8 | 37.9 | 0.3 | 61.8 | | Gentamicin | ≤0.5 | >32 | ≤0.5->32 | 86.8 | 0 | 13.2 | | Linezolid | 2 | 4 | 0.25-4 | 100 | 0 | 0 | | Trimethoprim-sulfamethoxazole | ≤0.12 | 8 | ≤0.12->8 | 87.8 | | 12.2 | | Vancomycin | 1 | 1 | ≤0.25-2 | 100 | 0 | 0 | Methicillin-susceptible S. epidermidis (42) | AFN-1252 | ≤0.008 | 0.03 | ≤0.008-0.06 | | | | | Cefazolin | 1 | 4 | ≤0.5-8 | 100 | 0 | 0 | | Ciprofloxacin | 4 | >16 | ≤0.06->16 | 47.2 | 0 | 52.8 | | Clindamycin | ≤0.12 | >8 | ≤0.12->8 | 61.1 | 0 | 38.9 | | Gentamicin | ≤0.5 | >32 | ≤0.5->32 | 58.3 | 10.2 | 31.5 | | Linezolid | 0.5 | 1 | ≤0.12-2 | 100 | 0 | 0 | | Trimethoprim-sulfamethoxazole | 1 | >8 | ≤0.12->8 | 58.3 | | 41.7 | | Vancomycin | 1 | 2 | ≤0.25-2 | 100 | 0 | 0 | Methicillin-resistant S. epidermidis (9) | AFN-1252 | ≤0.008 | ≤0.008 | ≤0.008 | | | | | Cefazolin | 64 | 128 | 32-128 | 0 | 0 | 100 | | Ciprofloxacin | >16 | >16 | 8->16 | 0 | 0 | 100 | | Clindamycin | >8 | >8 | ≤0.12->8 | 10.0 | 0 | 90.0 | | Gentamicin | 16 | >32 | ≤0.5->32 | 30.0 | 15.0 | 55.0 | | Linezolid | 1 | 1 | 0.5-1 | 100 | 0 | 0 | | Trimethoprim-sulfamethoxazole | 4 | 8 | ≤0.12->8 | 25.0 | | 75.0 | | Vancomycin | 1 | 2 | 1-2 | 100 | 0 | 0 | Streptococcus pneumoniae (489) | AFN-1252 | >4 | >4 | 4->4 | | | | | Penicillin | 0.06 | 0.25 | ≤0.03->8 | 79.3 | 15.7 | 5.0 | | Levofloxacin | 0.5 | 1 | ≤0.06-32 | 99.4 | 0 | 0.6 | | Ceftriaxone | ≤0.06 | 0.12 | ≤0.06-4 | 99.7 | 0.2 | 0.1 | | Linezolid | 0.5 | 1 | ≤0.12-2 | 100 | | | | Trimethoprim-sulfamethoxazole | ≤0.12 | 1 | ≤0.12->8 | 86.3 | 6.7 | 7.0 | | Vancomycin | ≤0.25 | ≤0.25 | ≤0.25-0.5 | 100 | | | Streptococcus pyogenes (73) | AFN-1252 | >4 | >4 | >4 | | | | | Penicillin | ≤0.03 | ≤0.03 | ≤0.03-0.12 | 100 | | | | Ciprofloxacin | 1 | 2 | 0.25-4 | | | | | Clindamycin | ≤0.06 | ≤0.06 | ≤0.06->8 | 97.3 | 0 | 2.7 | | Linezolid | 1 | 1 | 0.5-2 | 100 | | | | Trimethoprim-sulfamethoxazole | ≤0.12 | ≤0.12 | ≤0.12-0.25 | | | | | Vancomycin | 0.5 | 0.5 | ≤0.25-0.5 | 100 | | | Streptococcus agalactiae (86) | AFN-1252 | >4 | >4 | >4 | | | | | Penicillin | 0.06 | 0.25 | ≤0.03-0.12 | 100 | | | | Ciprofloxacin | 1 | 2 | 0.5->16 | | | | | Clindamycin | ≤0.06 | >8 | ≤0.06->8 | 85.2 | 2.3 | 12.5 | | Linezolid | 1 | 1 | ≤0.12-2 | 100 | | | | Trimethoprim-sulfamethoxazole | ≤0.12 | ≤0.12 | ≤0.12-0.25 | | | | | Vancomycin | ≤0.25 | ≤0.25 | ≤0.25-0.5 | 100 | | | Enterococcus faecalis (81) | AFN-1252 | >4 | >4 | >4 | | | | | Cefazolin | 32 | 128 | 0.5->128 | | | | | Ciprofloxacin | 2 | >16 | 0.25->16 | 38.3 | 26.6 | 35.1 | | Clindamycin | >8 | >8 | ≤0.12->8 | | | | | Linezolid | 2 | 2 | 0.5-4 | 98.7 | 1.3 | 0 | | Trimethoprim-sulfamethoxazole | ≤0.12 | 0.25 | ≤0.12->8 | | | | | Vancomycin | 1 | 2 | 0.5-4 | 100 | 0 | 0 | Enterococcus faecium (38) | AFN-1252 | >4 | >4 | 4->4 | | | | | Cefazolin | >128 | >128 | 32->128 | | | | | Ciprofloxacin | >16 | >16 | 1->16 | 12.1 | 5.2 | 82.7 | | Clindamycin | >8 | >8 | ≤0.12->8 | | | | | Linezolid | 2 | 2 | 1-4 | 91.4 | 8.6 | 0 | | Trimethoprim-sulfamethoxazole | ≤0.12 | >8 | ≤0.12->8 | | | | | Vancomycin | 0.5 | >32 | ≤0.25->32 | 87.9 | 0 | 12.1 | E. coli (599) | AFN-1252 | 4 | >4 | 0.5->4 | | | | | Cefazolin | 2 | 64 | ≤0.5->128 | 82.1 | 3.8 | 14.1 | | Ciprofloxacin | ≤0.06 | >16 | ≤0.06->16 | 75.2 | 0.3 | 24.5 | | Gentamicin | ≤0.5 | 16 | ≤0.5->32 | 88.9 | 0.5 | 10.6 | | Meropenem | ≤0.06 | ≤0.06 | ≤0.06-0.5 | 100 | 0 | 0 | | Piperacillin-tazobactam | 2 | 4 | ≤1->512 | 97.6 | 1.0 | 1.4 | | Trimethoprim-sulfamethoxazole | ≤0.12 | >8 | ≤0.12->8 | 73.4 | | 26.6 | K. pneumoniae (199) | AFN-1252 | >4 | >4 | 2->4 | | | | | Cefazolin | 2 | 8 | ≤0.5->128 | 91.4 | 1.8 | 6.8 | | Ciprofloxacin | ≤0.06 | 0.5 | ≤0.06->16 | 92.5 | 0.9 | 6.6 | | Gentamicin | ≤0.5 | ≤0.5 | ≤0.5->32 | 96.7 | 0.4 | 2.9 | | Meropenem | ≤0.06 | ≤0.06 | ≤0.06-0.25 | 100 | 0 | 0 | | Piperacillin-tazobactam | 2 | 8 | ≤1->512 | 96.7 | 1.3 | 2.0 | | Trimethoprim-sulfamethoxazole | ≤0.12 | 1 | ≤0.12->8 | 91.4 | | 8.6 | Klebsiella oxytoca (32) | AFN-1252 | >4 | >4 | 2->4 | | | | | Cefazolin | 8 | 32 | ≤0.5->128 | 60.0 | 23.0 | 17.0 | | Ciprofloxacin | ≤0.06 | 0.12 | ≤0.06->16 | 95.0 | 2.0 | 3.0 | | Gentamicin | ≤0.5 | ≤0.5 | ≤0.5->32 | 97.0 | 2.0 | 1.0 | | Meropenem | ≤0.06 | ≤0.06 | ≤0.06-0.12 | 100 | 0 | 0 | | Piperacillin-tazobactam | 2 | 16 | ≤1->512 | 90.0 | 1.0 | 9.0 | | Trimethoprim-sulfamethoxazole | ≤0.12 | ≤0.12 | ≤0.12->8 | 95.0 | | 5.0 | Enterobacter cloacae (72) | AFN-1252 | >4 | >4 | 4->4 | | | | | Cefazolin | 128 | >128 | 1->128 | 5.4 | 3.6 | 91.0 | | Ciprofloxacin | ≤0.06 | 0.5 | ≤0.06->16 | 91.6 | 0.6 | 7.8 | | Gentamicin | ≤0.5 | 1 | ≤0.5->32 | 96.4 | 0 | 3.6 | | Meropenem | ≤0.06 | ≤0.06 | ≤0.06-0.5 | 100 | 0 | 0 | | Piperacillin-tazobactam | 2 | 64 | ≤1->512 | 82.6 | 8.4 | 9.0 | | Trimethoprim-sulfamethoxazole | ≤0.12 | 1 | ≤0.12->8 | 91.6 | | 8.4 | Proteus mirabilis (34) | AFN-1252 | 4 | >4 | 2->4 | | | | | Cefazolin | 8 | 16 | 1-64 | 86.6 | 8.4 | 5.0 | | Ciprofloxacin | ≤0.06 | 2 | ≤0.06->16 | 82.4 | 8.4 | 9.2 | | Gentamicin | 1 | 2 | ≤0.5->32 | 95.8 | 0.8 | 3.4 | | Meropenem | ≤0.06 | ≤0.06 | ≤0.06-0.25 | 100 | 0 | 0 | | Piperacillin-tazobactam | 2 | 64 | ≤1-2 | 100 | 0 | 0 | | Trimethoprim-sulfamethoxazole | ≤0.12 | 2 | ≤0.12->8 | 90.8 | | 9.2 | Serratia marcescens (39) | AFN-1252 | 4 | >4 | 2->4 | | | | | Cefazolin | >128 | >128 | 2->128 | 0.9 | 0 | 99.1 | | Ciprofloxacin | 0.12 | 2 | ≤0.06-16 | 88.8 | 3.7 | 7.5 | | Gentamicin | ≤0.5 | 1 | ≤0.5->32 | 91.6 | 3.7 | 4.7 | | Meropenem | ≤0.06 | ≤0.06 | ≤0.06-2 | 100 | 0 | 0 | | Piperacillin-tazobactam | 2 | 8 | ≤1-128 | 94.4 | 4.7 | 0.9 | | Trimethoprim-sulfamethoxazole | 0.5 | 1 | ≤0.12-8 | 97.2 | | 2.8 | Pseudomonas aeruginosa (137) | AFN-1252 | >4 | >4 | >4 | | | | | Cefazolin | >128 | >128 | 16->128 | | | | | Ciprofloxacin | 0.5 | 16 | ≤0.06->16 | 66.0 | 11.0 | 23.4 | | Gentamicin | 4 | >32 | ≤0.5->32 | 60.1 | 19.0 | 20.9 | | Meropenem | 0.5 | 8 | ≤0.06->64 | 87.8 | 4.1 | 8.1 | | Piperacillin-tazobactam | 4 | 64 | ≤1->512 | 92.7 | 0 | 7.3 | | Trimethoprim-sulfamethoxazole | >8 | >8 | ≤0.12->8 | 14.5 | | 85.5 | Stenotrophomonas maltophilia (26) | AFN-1252 | >4 | >4 | >4 | | | | | Cefazolin | >128 | >128 | 128->128 | | | | | Ciprofloxacin | 4 | >16 | ≤0.06->16 | | | | | Gentamicin | 32 | >32 | ≤0.5->32 | | | | | Meropenem | >64 | >64 | ≤0.06->64 | | | | | Piperacillin-tazobactam | | >512 | 16->512 | | | | | Trimethoprim-sulfamethoxazole | 1 | >8 | ≤0.12->8 | 75.5 | | 24.5 | Acinetobacter baumannii (15) | AFN-1252 | >4 | >4 | >4 | | | | | Cefazolin | >128 | >128 | 64->128 | | | | | Ciprofloxacin | 0.25 | 4 | 0.12->16 | 88.0 | 0 | 12.0 | | Gentamicin | ≤0.5 | 1 | ≤0.5->32 | 92.0 | 0 | 8.0 | | Meropenem | 0.5 | 4 | ≤0.06-32 | 92.0 | 0 | 8.0 | | Piperacillin-tazobactam | 4 | >512 | ≤1->512 | 76.0 | 12.0 | 12.0 | | Trimethoprim-sulfamethoxazole | ≤0.12 | >8 | ≤0.12->8 | 84.0 | | 16.0 | M. catarrhalis (70) | AFN-1252 | >4 | >4 | 2->4 | | | | | Penicillin | >8 | >8 | ≤0.03->8 | | | | | Ciprofloxacin | ≤0.06 | ≤0.06 | ≤0.06 | 100 | | | | Gentamicin | ≤0.5 | ≤0.5 | ≤0.5 | | | | | Meropenem | ≤0.06 | ≤0.06 | ≤0.06 | | | | | Piperacillin-tazobactam | ≤1 | ≤1 | ≤1 | | | | | Trimethoprim-sulfamethoxazole | ≤0.12 | 0.5 | ≤0.12-1 | 94.0 | 6.0 | 0 | Open in a separate windowIn this study, AFN-1252 demonstrated narrow-spectrum, staphylococcus-specific in vitro activity and was inactive against all nonstaphylococcal potential human pathogens tested, including streptococci, enterococci, species of Enterobacteriaceae, nonfermentative gram-negative bacilli, and Moraxella catarrhalis. AFN-1252''s narrow-spectrum, staphylococcus-specific activity may be an attractive attribute for the treatment of patients with staphylococcal infections or the decolonization of patients with methicillin-resistant S. aureus because, compared to other treatment agents, it has a reduced risk of selecting for resistance in normal flora and other colonizing bacterial species and a reduced risk of altering normal flora and will potentially contribute minimally to the overall burden of resistance intrinsic with broad-spectrum agents.Only one previously published study has described the in vitro activity of AFN-1252 ( 9). In that study, all 350 isolates of methicillin-susceptible and 154 isolates of methicillin-resistant S. aureus were inhibited by concentrations of AFN-1252 of ≤0.12 μg/ml, results identical to the data presented in this study (Table ). All methicillin-susceptible ( n = 50) and methicillin-resistant ( n = 50) S. epidermidis isolates were inhibited by concentrations of AFN-1252 of ≤0.5 μg/ml (MIC 90s, 0.03 to 0.06 μg/ml) ( 9), two doubling dilutions higher than those reported in the present study (Table ). AFN-1252 has been reported to be inactive in vitro against gram-positive anaerobes, including Bifidobacterium spp., Clostridium perfringens, Clostridium difficile, Eubacterium lentum, Lactobacillus spp., Peptostreptococcus spp., and Propionibacterium acnes, as well as gram-negative anaerobes, including Bacteroides spp., Fusobacterium spp., Porphyromonas spp., Prevotella spp., and Veillonella parvula ( 8).Our data revealed that organisms other than staphylococci, specifically M. catarrhalis, Escherichia coli, and Klebsiella pneumoniae, that possess FabI as their sole enoyl-ACP reductase ( 10) were nonsusceptible to AFN-1252. Staphylococci, E. coli, M. catarrhalis, and Haemophilus influenzae have been shown previously to possess FabI and to lack an alternative enzyme or rescue pathway ( 1). We speculate that M. catarrhalis, E. coli, and K. pneumoniae are not susceptible to AFN-1252, despite possessing FabI as their sole enoyl-ACP reductase, because these gram-negative organisms may possess an efflux mechanism for or present a permeability barrier to AFN-1252. AFN-1252 may be a substrate for the acrAB efflux pump of E. coli, as the AFN-1252 MIC for an acrAB-deficient mutant (AG100a Δ acrAB) has been demonstrated previously to be 0.016 μg/ml while the MIC for the parental strain (AG100) is >32 μg/ml ( 8). The FabI active sites of these gram-negative bacteria have structural differences from the S. aureus active site used to direct the iterative structure-guided development of AFN-1252 (Affinium Pharmaceuticals, Inc., unpublished data). Alternatively, FabI may be overexpressed in these species, as the overexpression of FabI in S. aureus has been reported to reduce the activity of triclosan, an agent whose mechanism of action also involves interaction with FabI ( 11).In conclusion, escalating rates of resistance may limit the clinical utility of some currently marketed antibacterial agents and underlie the search for new classes of agents with novel mechanisms of action. AFN-1252 is a promising new agent with the potential to treat patients with staphylococcal infections known or suspected to be resistant to conventional antistaphylococcal therapies in both hospital and outpatient settings. These data support the continued development of AFN-1252 for the treatment of patients with resistant staphylococcal infections. 相似文献
18.
A comparative "cost-efficiency" pharmacoeconomic analysis was made for 5 different anti-emitting drugs, i.e. for "Navoban", "Zofran" (intravenous administration, 8 mg; and suppositories, 16 mg) and for "Metipred" (methylprednisolone) used in aesthetic and reconstructive surgeries of 86 patients. All the drugs were found to be effective for the prevention of PONV. Clinically, the efficiency decreased in the following order: "Novoban" and "Zofran" suppositories 16 mg, "Metiored" and "Zofran" intravenous administration 8 mg. As for "cost-efficiency", preference should be given to "Metipred". 相似文献
19.
The terms "alternative" or "unconventional" have been used to describe any therapy used instead of conventional approaches. Conventional approaches, known as "standard" or "traditional" or "biomedical" approaches, have had broad application in Western medicine. Complementary and alternative medicine has been referred to as "integrative," "integrated," or "complementary" when therapies are combined with conventional approaches, such as those for cancer. 相似文献
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