Inhibitory and bactericidal effects of telithromycin (HMR 3647, RU 56647) and five comparative antibiotics, used singly and in combination, against vancomycin-resistant and vancomycin-susceptible enterococci

The inhibitory and bactericidal effects of telithromycin (HMR 3647, RU 66647) were compared with those of gentamicin, ampicillin, erythromycin, azithromycin and vancomycin against 74 strains of enterococci (34 Enterococcus faecalis and 40 Enterococcus faecium) by agar dilution, broth dilution, time kill assays and postantibiotic effect (PAE). The telithromycin MIC(90) for vancomycin-sensitive (VSE) E. faecalis strains tested using the agar dilution method was 8 microg/ml. For a different group of VSE E. faecalis strains tested using the broth dilution method it was 0.06 microg/ml The telithromycin MIC(90)s for vancomycin-resistant (VRE) and VSE E. faecium strains, determined using the agar dilution method, were 4 and 8 microg/ml, respectively, while for a different set of VRE and VSE E. faecium strains tested using the broth macrodilution method, they were 32 and 16 microg/ml, respectively. Telithromycin MBC(90)s for E. faecalis were 4-6 tubes higher and for E. faecium 3-5 tubes higher, respectively, than the MIC(90)s. In time kill assays, telithromycin had bactericidal activity against only 1 of 7 E. faecium strains; for all other E. faecium and E. faecalis strains, only inhibitory activity was demonstrated. Neither synergy nor drug interference was observed when telithromycin was used in combination with ampicillin, vancomycin or gentamicin. At 10 times the MIC, the PAE of telithromycin against E. faecalis was 2.8 h, while for E. faecium it was 1.6 h. Telithromycin should be evaluated for therapy of enterococcal infections, including those caused by VRE organisms. However, because of the strain-to-strain variability in susceptibility to telithromycin, MIC determinations are important, especially for erythromycin-resistant strains.     

Susceptibility patterns of enterococci causing infections

Enterococci are among the common organisms associated with hospital-acquired infections. We examined in vitro activities of different antibiotics to 103 enterococcal isolates. Minimal inhibitory concentrations (MICs) of penicillin G, ampicillin, gentamicin, ciprofloxacin, ofloxacin, levofloxacin, grepafloxacin, trovafloxacin and gemifloxacin were determined by broth microdilution testing method. Among the isolates 71 (69%) were identified as E. faecalis and 32 (31%) as E. faecium. While over 75% of E. faecium isolates were resistant to penicillin and ampicillin, approximately 25% of E. faecalis isolates were resistant to penicillin and ampicillin. None of the E. faecalis and E. faecium isolates were resistant to vancomycin. While 17 (52%) of E. faecium isolates exhibited high-level gentamicin resistance (HLGR), high level streptomycin resistance (HLSR) was detected in 24 (74%) of the isolates. In contrast, HLGR and HLSR rates for E. faecalis were 14 (20%) and 22 (31%), respectively. Both HLGR and HLSR were detected with higher frequency in ampicillin resistant isolates. Among fluoroquinolones, gemifloxacin and trovafloxacin were the most potent antibiotics tested. There was no increase in MIC90 values of the fluoroquinolones in ampicillin resistant isolates in comparison with ampicillin susceptible isolates. Our data suggest newer fluoroquinolones would be good alternative agents to use especially for combination drug therapy where enterococci with ampicillin resistance and HLAR are prevalent.     

Absence of synergistic activity between ampicillin and vancomycin against highly vancomycin-resistant enterococci.

The emergence of clinical enterococcal isolates resistant to both ampicillin and vancomycin is a cause of great concern, as there are few therapeutic alternatives for treatment of infections caused by such organisms. We evaluated the effects of the combination of ampicillin with vancomycin against vancomycin-resistant clinical enterococcal isolates. Using both the checkerboard technique and time-kill curves, we examined 28 strains of enterococci (17 Enterococcus faecalis and 11 Enterococcus faecium strains) with different levels of resistance to vancomycin. Of these, 15 strains were also highly gentamicin resistant, and 9 demonstrated resistance to ampicillin. Only seven strains of E. faecalis were inhibited synergistically by the combination of vancomycin with ampicillin, and even then, the concentrations of vancomycin at which synergism was demonstrated were above levels achievable in serum. None of the ampicillin-resistant isolates (all E. faecium) were inhibited synergistically at any concentration of the drugs. In no instance was bactericidal synergism observed, and in most cases the combination resulted in less killing than with ampicillin alone. Antagonism was not observed at clinically relevant concentrations. The results of this study suggest that the combination of vancomycin with ampicillin has little to offer against these emerging pathogens.     

The bactericidal activity and postantibiotic effect of trospectomycin.

Trospectomycin sulfate (trospectomycin, TRS) is a novel, broad-spectrum, aminocyclitol antibiotic that is being developed clinically for the treatment of upper respiratory tract infections, bacterial vaginosis, pelvic inflammatory disease, and gonorrhea. This study investigated the bactericidal activity (by time-kill kinetics) and the postantibiotic effect (PAE) of TRS. Species-dependent bacteriostatic/bactericidal activity was observed for TRS; the antibiotic was bacteriostatic for Staphylococcus epidermidis, Enterococcus faecalis, and Escherichia coli, and bactericidal for Haemophilus influenzae, Neisseria gonorrhoeae, Moraxella catarrhalis, and Bacteroides fragilis (one of two test strains). When TRS was tested at four times its minimum inhibitory concentration or at a maximum test concentration of 32 micrograms/ml, with a 1-hr exposure period, the following PAE values were recorded: S. epidermidis 30032, 1.8 hr, En. faecalis ATCC 29212, 1.6 hr, E. coli UC 311, 1.5 hr, E. coli UC 9451, 1.5 hr, H. influenzae 30063, greater than 4.0 hr, B. fragilis ATCC 25285, 5.2 hr, and B. fragilis UC 12199, 6.7 hr. The broad-spectrum PAE that was observed for TRS is somewhat unique compared with other antibiotics.     

In-vitro evaluation of cefpirome (HR 810), teicoplanin and four other antimicrobials against enterococci

In-vitro activities of cefpirome (HR 810), a fourth generation cephalosporin, and teicoplanin were compared with those of ampicillin, piperacillin, and vancomycin against 56 clinical isolates of enterococci. Cefpirome had good activity with the MIC90 and MBC90 being 4 and 16 mg/l. Ampicillin and piperacillin had MBC90 of 4 and 16 mg/l. Teicoplanin was extremely active with the MIC90 being 1.6 mg/l while vancomycin had poor cidal activity with the MBC90 being 16 mg/l. A decrease in activity of cefpirome was noted when the inoculum size was increased from 10(3) to 10(7) organisms per ml. Synergy was demonstrated against most Streptococcus faecium isolates with a combination of cefpirome and gentamicin or piperacillin. Against Str. faecalis, with a similar combination, synergy was seen in less than 50% isolates. No antagonism was noted with any of the antibiotic combinations.     

肠球菌耐药趋势研究及抗感染用药建议

目的分析该院各类临床标本中分离的肠球菌对常用抗生素耐药情况,为临床医生提供抗肠球菌感染的治疗对策。方法应用Vitek微生物系统回顾性统计分析近3年来该院肠球菌的耐药情况。结果3年来,肠球菌属的构成比发生改变,屎肠球菌分离率有增加趋势;粪肠球菌和屎肠球菌引起的感染部位有差异,屎肠球菌主要引起泌尿系统感染(47.3％)。不同标本来源粪肠球菌对常用抗生素耐药率明显不同,粪肠球菌引起的泌尿系统感染可选用呋喃妥因或万古霉素。万古霉素对粪肠球菌的MIC50呈上升趋势;四环素MIC50呈下降趋势;呋喃妥因、青霉素-G的MIC50无明显变化;氨苄青霉素、环丙沙星对粪肠球菌的MIC50趋势不定。呋喃妥因对屎肠球菌MIC50呈上升趋势;氨苄青霉素、四环素、万古霉素MIC50呈下降趋势;环丙沙星、青霉素-G的MIC50无明显变化。结论临床医生应合理选用抗生素,延长抗生素的使用寿命,使肠球菌耐药得到有效控制。     

In-vitro and in-vivo activity of cefpirome (HR 810) against methicillin-susceptible and -resistant Staphylococcus aureus and Streptococcus faecalis

With cefpirome (HR 810) the MICs for both methicillin-resistant Staphylococcus aureus (MRSA) and for Streptococcus faecalis were 8.0 mg/l. At 4 x MIC, cefpirome killed MRSA as rapidly as did vancomycin while for enterococci, cefpirome, vancomycin or ampicillin alone were not bactericidal. However, all agents were bactericidal when combined with 2 mg/l of gentamicin, although gentamicin combined with cefpirome showed a smaller decrease in cfu/ml than the combination with ampicillin or vancomycin. A mouse thigh infection model was developed in which the thigh muscle was infected with bacteria and either no therapy or concurrent antibiotic therapy was initiated. On the subsequent day, the entire thigh muscle was quantitatively cultured. In this model, the numbers of enterococci at the infection site at 24 h were reduced by 2.1 logs with no treatment, 2.6 with cefpirome (25 mg/kg/day), 2.8 with ampicillin (150 mg/kg/day), and 2.7 with vancomycin (25 mg/kg/day). For MRSA the reductions were 1.1 logs with no therapy, 2.8 with vancomycin, and 3.0 with cefpirome. The apparent enhanced in-vivo activity of cefpirome for MRSA argues for further evaluation of this antibiotic for treatment of MRSA and other Gram-positive cocci, including enterococci.     

Comparative activity of imipenem (N-formimidoyl thienamycin) on enterococci and its interactions with aminoglycosides

Activity of imipenem (N-formimidoyl thienamycin, ampicillin and vancomycin against 27 Streptococcus faecalis and 5 Str. faecium was determined. Also evaluated were the interactions of imipenem, ampicillin and vancomycin with streptomycin or amikacin or sissomicin. Imipenem showed the most inhibitory activity against Str. faecalis with MIC50 and MIC90 values 0.5 and 2 mg/l respectively, Str. faecium strains were less susceptible to imipenem with MIC50/MIC90 values of 2/16 mg/l. Imipenem showed good bactericidal activity against both groups of strains with MBC50/MBC90 values of 1/4 and 4/16 mg/l respectively. The most favourable interactions (synergy and addition) of imipenem were with streptomycin (72.2%) and sissomicin (53.2%). Combinations containing amikacin were the least favourable. Similar results were obtained with these combinations against Str. faecium.     

Novel antibiotic regimens against Enterococcus faecium resistant to ampicillin, vancomycin, and gentamicin.

Enterococci have emerged as significant nosocomial pathogens. Enterococci with resistance to commonly used antibiotics are appearing more frequently. We encountered at our institution several infections caused by Enterococcus faecium with high-level resistance to ampicillin, vancomycin, and gentamicin. The optimal antibiotic therapy for serious infections with unusually resistant enterococci has not been established. Using time-kill studies, we tested the effectiveness of various antibiotic combinations against 15 isolates of multidrug-resistant enterococci. No antibiotic was consistently effective when used alone. The combination of ampicillin plus ciprofloxacin was bactericidal for the 12 isolates for which the ciprofloxacin MIC was < or = 8 micrograms/ml. The combination of ciprofloxacin plus novobiocin also demonstrated activity against these isolates. No combination was found to be bactericidal for the remaining three isolates, which were highly ciprofloxacin resistant. These antibiotic combinations may be important for the future treatment of serious infections caused by these resistant pathogens.     

In vitro activity of daptomycin versus linezolid and vancomycin against gram-positive uropathogens and ampicillin against enterococci, causing complicated urinary tract infections

OBJECTIVES: The existing therapeutic options for complicated urinary tract infections (UTI) caused by gram-positive uropathogens are not always optimal. Therefore, newer antimicrobials have to be assessed. METHODS: The antimicrobial activity of daptomycin was tested versus linezolid, vancomycin, and ampicillin (enterococci on ly), against pathogens from three different collections: (1) Uropathogens from hospitalized urological patients with complicated and/or hospital-acquired UTIs of the Urologic Clinic, Hospital St. Elisabeth, Straubing. (2) Uropathogens from a multicenter study comprising 37 urological centers throughout Germany. (3) Methicillin-resistant Staphylococcus aureus (MRSA) isolates of patients and staff within the Hospital St. Elisabeth, Straubing. Genotyping of the latter isolates was performed by pulsed-field gel electrophoresis. The minimal inhibitory concentrations (MIC) of daptomycin, linezolid, vancomycin, and ampicillin (only tested against enterococci) were determined by an agar dilution method using a multipointer with an inoculum of 10(4) CFU per point. RESULTS: For all methicillin-susceptible Staphylococcus aureus (n = 25), MRSA (n = 49), methicillin-susceptible coagulase-negative staphylococci (n = 129), methicillin-resistant coagulase-negative staphylococci (n = 33), for Enterococcus faecalis (n = 289), and for Enterococcus faecium (n = 4) the MICs ranged up to 2 mg/l (daptomycin, linezolid), up to 4 mg/l (vancomycin), and up to 8 mg/l (ampicillin, enterococci only) indicating that all strains were susceptible to the antibiotics tested. CONCLUSIONS: According to the in vitro activity daptomycin may be considered a promising antibacterial agent for the treatment of complicated UTI caused by gram-positive uropathogens. Thus, daptomycin should be evaluated in a clinical study.     

Bactericidal activity of netilmicin compared with gentamicin and streptomycin, alone and in combination with penicillin, against penicillin tolerant viridans streptococci and enterococci

Netilmicin was compared with gentamicin and streptomycin for in-vitro activity against 30 strains of penicillin-tolerant streptococci including 16 strains of enterococci. Both netilmicin and gentamicin tested alone at 4 mg/l caused 99.9% kill of more than half of the 13 strains of viridans streptococci tested, whereas streptomycin, 4 mg/l, had no bactericidal effect against these strains. Netilmicin, gentamicin and streptomycin tested alone at 8.0 mg/l against 10 strains of Streptococcus faecalis resulted in 99.9% kill of six, one and zero strains respectively. Combinations of penicillin with 2 mg/l of either netilmicin or gentamicin resulted in bactericidal synergy against 12 of 13 strains of viridans streptococci and all 10 strains of S. faecalis after 18 to 24 h incubation. Parallel experiments showed that higher concentration of penicillin were required to obtain 99.9% kill of 10 streptococcal strains when 4 mg/l streptomycin was compared with 2 mg/l of the other aminoglycosides. Killing curves showed similar bactericidal synergy for netilmicin-penicillin and gentamicin-penicillin combinations against most streptococci tested after 24 h incubation but there was sometimes a greater bactericidal effect noted with netilmicin after only 6 h incubation of the broth or after 48 h incubation. The results of this in-vitro study suggest that netilmicin is at least as effective as gentamicin as a bactericidal synergic agent with penicillin against penicillin-tolerant viridans streptococci and S. faecalis strains isolated from patients with endocarditis. Neither gentamicin or netilmicin were effective as bactericidal synergic agents with penicillin against 4 of 6 strains of S. faecium tested.     

Species identification and antibiotic susceptibility testing of enterococci isolated from hospitalized patients.

A total of 236 enterococci from hospitalized patients were identified to the species level, and their susceptibilities to 11 antibiotics were determined. Overall, 195 (82.6%) and 38 (16.1%) isolates were identified as Enterococcus faecalis and E. faecium, respectively, but the species distribution as determined from blood culture isolates differed markedly. A total of 27 (63.2%) E. faecium isolates, but no E. faecalis strains, were ampicillin resistant (MIC, greater than 8 micrograms/ml). High-level gentamicin resistance (MIC, greater than 500 micrograms/ml) was found in 8.2% of E. faecalis isolates but was not seen in other species.     

In vitro activity of ampicillin/sulbactam against enterococci determined by the time-kill method

Time-kill studies demonstrated that at clinically achievable serum concentrations, ampicillin/sulbactam was equivalent in activity to ampicillin alone against non-beta-lactamase producing isolates of Enterococcus faecalis and Enterococcus faecium. Sulbactam possessed no antibacterial activity against these organisms. It is not yet known if the activity of ampicillin will be increased with the addition of sulbactam when tested against beta-lactamase-producing enterococci.     

Bactericidal activities of peptide antibiotics against multidrug-resistant Enterococcus faecium.

Multidrug-resistant Enterococcus faecium has emerged as a serious pathogen for which no effective therapy has been established. In this report, we describe the activities of two peptide antibiotics, ramoplanin and daptomycin, against 15 isolates of E. faecium resistant to vancomycin, ampicillin, and aminoglycosides using time-kill experiments. Both antibiotics were rapidly bactericidal when tested in broth; however, the addition of 50% serum resulted in significant regrowth. The combination of ampicillin with either ramoplanin or daptomycin largely prevented this regrowth. These peptide antibiotics showed good activity against these pathogens. While the development of daptomycin has been halted, ramoplanin may hold promise for the therapy of multidrug-resistant E. faecium, especially when combined with ampicillin.     

Serum bactericidal activities of high-dose daptomycin with and without coadministration of gentamicin against isolates of Staphylococcus aureus and Enterococcus species

The purpose of this experiment was to evaluate the pharmacokinetics and serum bactericidal titers (SBTs) of daptomycin alone and in combination with gentamicin against strains of Staphylococcus aureus and enterococci to determine if there might be any benefit to the addition of the aminoglycoside. A multiple-dose, randomized crossover study was performed in 11 healthy volunteers to evaluate the steady-state pharmacokinetic profile of 6 mg/kg of body weight daptomycin once daily with or without 1 mg/kg gentamicin every 8 h. SBTs were determined against clinical isolates of nosocomial (MRSA 494) and community-acquired (CA-MRSA 44) methicillin-resistant S. aureus, vancomycin-susceptible Enterococcus faecalis (VSEF 49452), vancomycin-resistant Enterococcus faecium (VREF 80), and quality control strains of methicillin-susceptible S. aureus (ATCC 29213) and vancomycin-susceptible E. faecalis (ATCC 29212). Enhancement of bactericidal activity was evaluated by calculating and comparing the areas under the bactericidal curve (AUBC) for each dosing regimen against each isolate. The area under the concentration-time curve from 0 to 24 h and clearance for daptomycin alone were 645 +/- 91 microg.h/ml and 9.47 +/- 1.4 mg/h/kg, respectively, compared with 642 +/- 69 microg.h/ml and 9.45 +/- 1.0 mg/h/kg for daptomycin plus gentamicin. Daptomycin alone displayed sustained bactericidal activity against five of the six isolates over the entire 24-h dosing interval; bactericidal activity was maintained for 8 h against VREF 80. Mean AUBCs for daptomycin alone ranged from 935 to 1,263 and 36 to 238 against staphylococcal and enterococcal isolates, respectively, compared with 902 to 972 and 34 to 213 against staphylococci and enterococci when coadministered with gentamicin. The results of this study suggest that the addition of gentamicin does not alter the pharmacokinetic profile or enhance the bactericidal activity of daptomycin against staphylococcal or enterococcal isolates.     

In vitro activities of quinolones against enterococci resistant to penicillin-aminoglycoside synergy.

The MICs and MBCs of CI-934, ciprofloxacin, difloxacin (A-56619), A-56620, norfloxacin, enoxacin, amifloxacin, and coumermycin were determined for 43 clinical isolates of Enterococcus faecalis known to be resistant to penicillin-aminoglycoside synergy. Results were compared with those obtained for 37 synergy-susceptible E. faecalis and 22 Enterococcus faecium strains. Although no substantial differences in quinolone activities were observed between synergy-resistant and -susceptible E. faecalis strains, CI-934 and ciprofloxacin were the drugs that demonstrated the greatest bactericidal activity against both types of E. faecalis. The MBCs of the other quinolones were generally within a single twofold dilution of the MICs, but their antienterococcal activity did not approach that of CI-934 or ciprofloxacin. The MBCs for 90% of the isolates of CI-934 for synergy-resistant and -susceptible E. faecalis strains were 1 and less than or equal to 0.5 microgram/ml, respectively. The ciprofloxacin MBC for 90% of the E. faecalis strains tested was 1 microgram/ml. For E. faecium isolates the CI-934 and ciprofloxacin MBCs for 90% of the isolates were 8 and 4 micrograms/ml, respectively. Time-kill assays performed with synergy-susceptible enterococcal strains showed that the bactericidal activities of both CI-934 and ciprofloxacin were less than those of the penicillin-aminoglycoside combinations tested. However, against synergy-resistant isolates the activities of these two quinolones were comparable with and sometimes greater than those of penicillin-aminoglycoside combinations.     

Antibiotic Susceptibility of Streptococcus bovis and Other Group D Streptococci Causing Endocarditis

Seventy-four strains of Streptococcus bovis and 35 strains of enterococci (Streptococcus faecalis and its varieties, Streptococcus faecium and Streptococcus durans), most of which were isolated from patients with endocarditis, were tested for their susceptibility to penicillin, ampicillin, erythromycin, cephalothin, vancomycin, methicillin, tetracycline, chloramphenicol, kanamycin, streptomycin, and gentamicin. Minimal inhibitory concentrations (MIC) and minimal bactericidal concentrations (MBC) were determined by a microtiter broth dilution technique. All of these organisms are group D streptococci, but the S. bovis strains are not enterococci. On the basis of both MIC and MBC, the S. bovis strains were much more susceptibile in general to antibiotics then were the enterococcal strains. For the S. bovis strains, the lowest MICs were obtained with penicillin, ampicillin, and erythromycin, and the lowest MBCs with penicillin and ampicillin. Although these antibiotics were also the most active against the enterococci, the MICs and MBCs were much higher than obtained with the S. bovis strains. Gentamicin was the most active aminoglycoside. On the basis of in vitro susceptibility results, the S. bovis strains resemble the viridans streptococci rather than enterococci.     

Vancomycin tolerance in enterococci

BACKGROUND: Tolerance can be defined as the ability of bacteria to grow in the presence of high concentrations of bactericide antimicrobics, so that the killing action of the drug is avoided but the minimal inhibitory concentration (MIC) remains the same. We investigated vancomycin tolerance in the Enterococcus faecium and Enterococcus faecalis strains isolated from different clinical specimens. METHODS: Vancomycin was obtained from Sigma Chemical Co. We studied 100 enterococci strains. Fifty-six and 44 of Enterococcus strains were idendified as E. feacalis and E. faecium, respectively. To determine MICs and minimal bactericidal concentration (MBC), we inoculated strains from an overnight agar culture to Muller-Hinton broth and incubated them for 4-6 h at 37 degrees C with shaking to obtain a logarithmic phase culture. The inoculum was controlled by performing a colony count for each test. We determined MBC values and MBC/MIC ratios to study tolerance to vancomycin. Vancomycin tolerance was defined as a high MBC value and an MBC/MIC ratio > or =32. RESULTS: Fifty-six and 44 of the Enterococcus strains were identified as E. faecium and E. faecalis, respectively. Thirty-one E. faecium and 48 E. faecalis were found to be susceptible to vancomycin and these susceptible strains were included in this study. The MICs of susceptible strains ranged from < or =1 to 4 mg/l, the MBCs were > or =512 mg/l. Tolerance was detected in all E. faecalis and E. faecium strains. The standard E. faecalis 21913 strain also exhibited tolerance according to the high MBC value and the MBC/MIC ratio. We defined the tolerant strains as having no bactericidal effect and MBC/MIC > or =32. We found that a 100% tolerance was present in susceptible strains. CONCLUSIONS: One of the hypotheses for tolerance is that tolerant cells fail to mobilize or create the autolysins needed for enlargement and division. Our data suggests that tolerance may compromise glycopeptide therapy of serious enterococci infections. To add an aminoglycoside to the glycopeptide therapy unless MBCs are unavailable can be useful in the effective treatment of serious Enterococcus infections.     

258株肠球菌耐药性分析及耐万古霉素基因检测

目的研究肠球菌的耐药率及耐万古霉素肠球菌(VRE)的耐药表型和基因型。方法按照美国临床和实验室标准化研究所(CLSI)2009年推荐的微量稀释法进行临床分离肠球菌对各类药物的最小抑菌浓度(MIC)检测,VRE进一步用E-test药敏试验确认;PCR法检测VRE的耐药基因。结果 2010年7月至2011年11月沈阳军区总医院共检出粪肠球菌95株,屎肠球菌163株。粪肠球菌对万古霉素、替考拉宁保持较高敏感度,对氨苄西林、青霉素、呋喃妥因三种抗菌药物敏感度也在65%以上,对其他抗菌药物敏感度低,统计期内未检出耐万古霉素粪肠球菌菌株。屎肠球菌对多数抗菌药物表现为耐药,对氯霉素敏感率为70%,对万古霉素、替考拉宁敏感度下降,为90.7%。期间检出15株VRE,其耐药表型为多重耐药,PCR扩增结果显示,15株万古霉素耐药屎肠球菌VanA基因扩增均为阳性,产物长度在700～1000bp之间,约783bp,符合预期;VanB、VanC引物扩增均阴性。15株万古霉素耐药屎肠球菌对多数抗菌药物耐药,仅对氯霉素、四环素相对敏感,对万古霉素MIC>256mg/L,对替考拉宁也表现为耐药。结论屎肠球菌耐药性高于粪肠球菌,VRE多为多重耐药,给临床治疗带来困难,医院应加强对其预防监测。     

Antimicrobial Susceptibility Patterns of Enterococci Causing Infections in Europe

In vitro susceptibilities of 4,208 enterococci (83% Enterococcus faecalis isolates, 13.6% Enterococcus faecium isolates, and 3.4% isolates of other species) from patients in 27 European countries towards 16 antibiotics were determined. High-level resistance to gentamicin varied by country (range, 1 to 49%; mean, 22.6% +/- 12. 3%) and per species (19.7% E. faecalis isolates, 13.6% E. faecium isolates, 3.4% by other species). Vancomycin resistance was detected in 0.06% E. faecalis, 3.8% E. faecium, and 19.1% isolates of other species. All enterococci were susceptible to LY 333328 and everninomicin, and 25% of E. faecalis isolates and 85% of other enterococci were susceptible to quinupristin-dalfopristin. The MIC of moxifloxacin and trovafloxacin for ciprofloxacin-susceptible E. faecalis at which 90% of the isolates were inhibited was 0.25 to 0.5 microg/ml.