Antimicrobial susceptibility of Pseudomonas aeruginosa isolated at Kochi Municipal Central Hospital in the last 3 years

Antimicrobial susceptibility of Pseudomonas aeruginosa isolated at Kochi Municipal Central Hospital between 2001 and 2003 was assessed according to the NCCLS interpretive criteria. 1. The piperacillin-susceptible rate was 92.9%. 2. Among cephem antibiotics, the ceftazidime-susceptible rate was the highest (96.0%). 3. As for aminoglycosides, susceptibility to tobramycin and amikacin remained with a susceptible rate of 93.2% and 94.8%, respectively. 4. The carbapenem-susceptibility remained high. The susceptible rate for meropenem (94.1%) was higher than that for imipenem (88.3%). 5. Acquisition of resistance was observed in urinary isolates. Four multi-drug resistant P. aeruginosa, which are resistant to all of imipenem, amikacin and ofloxacin were isolated in this study and all were isolated from urine. 6. Of 388 isolates, 34 isolates were resistant to imipenem, but no positive isolate was found in screening of metallo-beta-lactamase-producing bacteria.     

Antimicrobial susceptibility profiles of Pseudomonas aeruginosa and Staphylococcus aureus isolated in Italy from patients with hospital-acquired infections

Here we report the results of the Sentinel Project 2000 and give the susceptibility to selected antibiotics of 108 Pseudomonas aeruginosa and 108 Staphylococcus aureus strains isolated from patients with hospital-acquired lower respiratory tract infections. In P. aeruginosa, susceptibility to aztreonam and ciprofloxacin was lower than 50%. The resistance rate to beta-lactams was up to 25% and to amikacin 15.7%. Blood isolates showed 80-90% susceptibility to all antibiotics tested except for aztreonam and tobramycin. Overall, oxacillin resistance in S. aureus was 45%, reaching 64.3% among the bronchoalveolar lavage isolates, and 42.9% among the blood isolates. These worrying results confirm the need for continuous monitoring of bacterial resistance trends in the hospitals, mainly in ICUs.     

Antimicrobial susceptibility of Streptococcus pneumoniae, Haemophilus influenzae and Pseudomonas aeruginosa isolated in major hospitals in Nagano prefecture

We determined the minimum inhibitory concentration (MIC) of various antimicrobial agents against 140 strains of Streptococcus pneumoniae, 131 strains of Haemophilus influenzae and 178 strains of Pseudomonas aeruginosa isolated from respiratory organs in 28 affiliated hospitals in Nagano prefecture between December 2002 and February 2003. The results of this report were as followed: 1. All 140 strains of S. pneumoniae were classified into 3 groups; penicillin-susceptible S. pneumoniae (PSSP) (47.1%), penicillin-intermediate S. pneumoniae (PISP) (43.6%) and penicillin-resistant S. pneumoniae (PRSP) (9.3%). 2. Carbapenems and glycopeptide (vancomycin) had highly potent antimicrobial activity against PISP and PRSP like PSSP. However, some of PISP or PRSP isolates were resistant to cephalosporins and a fluoroquinolone (levofloxacin). 3. All 131 strains ofH. Influenzae were also classified into three groups; ampicillin sensitive H. influenzae (73.3%), beta-lactamase producing ampicillin resistant H. influenzae (BLPAR) (8.4%) and beta-lactamase negative ampicillin resistant H. influenzae (BLNAR) (18.3%). 4. Carbapenems and a fluoroquinolone had highly potent antimicrobial activity against BLPAR and BLNAR. However, there were clear differences among 4 carbapenems for the antimicrobial activity. Ceftriaxone (CTRX) was the most active among cepharosporins in this study. 5. The rate of P. aeruginosa isolates resistant to carbapenems, a fluoroquinolone and aminoglycosides were about 11 to approximately 16%, 15% and 0.6 to approximately 8%, respectively. None of the strains was resistant to all 3 antimicrobial classes, but 3 strains were resistant to combination of 2 classes. 6. The MIC50 and MIC90 values of various antibiotics against S. pneumoniae, H. influenzae and P. aeruginosa were different in all 4 regions. In conclusion, the antimicrobial surveillance programs are important for guiding empiric therapy and for focusing interventional control of antimicrobial resistance in regions and hospitals.     

Antimicrobial susceptibility of Pseudomonas aeruginosa isolated from urine at one hospital to mainly carbapenem and fluoroquinolone drugs

We tested the drug susceptibility to 8 anti-pseudomonal agents of 97 strains of Pseudomonas aeruginosa isolated from urine between January 1998 and May 2004. The results were as follows. 1. Antimicrobial activity was, in order of superiority to biapenem (BIPM), meropenem (MEPM), ciprofloxacin (CPFX), imipenem (IPM), pazufloxacin (PZFX), amikacin (AMK), ceftazidime (CAZ), piperacillin (PIPC). 2. The resistance rate (intermediate+resistance) to carbapenem drugs was 10.3% for BIPM and MEPM, and 13.4% for IPM. Many of the IPM-resistant strains showed crossover resistance with BIPM and MEPM. 3. The resistance rate (intermediate+resistance) to fluoroquinolone drugs was 23.7% for CPFX and 20.6% for PZFX. 4. One strain showed simultaneous resistance to IPM = 16 microg/mL, CPFX = 4 microg/mL, and AMK = 32 microg/mL, and produced IMP-1 metallo-beta-lactamase. Susceptibility of P. aeruginosa isolated from urine developed resistance to fluoroquinolone drugs. It is important to promote appropriate use of antimicrobial agents and continue to survey emerging resistance in the clinical isolates.     

Antimicrobial use and Pseudomonas aeruginosa susceptibility profile in a cystic fibrosis centre

The susceptibility patterns of 1315 mucoid and non-mucoid Pseudomonas aeruginosa strains from 224 patients were determined along with antibiotic utilisation in a Cystic Fibrosis Centre from 1993 to 1997. Ceftazidime was the most active agent (86.0% sensitive isolates), followed by piperacillin-tazobactam (81.7%), aztreonam (80.3%), imipenem (80%), piperacillin (76.8%), tobramycin (76.5%), ciprofloxacin (73.7%), ticarcillin (72.4%), ticarcillin-clavulanic acid (70.2%), amikacin (69.5%), netilmicin (56.5%), meropenem (79%) and imipenem (75.5%). The most frequently used compounds were nebulized colistin (mean+/-S.D., 109+/-45 defined daily doses per 1000 patients per day), followed by ciprofloxacin (98+/-8), tobramycin (55+/-9), ceftazidime (31+/-8) and amikacin (55+/-9). The mean antibiotic consumption by our CF patients was 413+/-47 defined daily doses per 1000 patients per day. Trend testing showed a significant decline of susceptibility to aminoglycosides, imipenem and ciprofloxacin, while the susceptibility of P. aeruginosa to piperacillin and ceftazidime was stable.     

Antimicrobial susceptibility of Streptococcus pneumoniae and Haemophilus influenzae isolated in major hospitals in Nagano Prefecture

We determined the minimum inhibitory concentration (MIC) of various antimicrobial agents against 108 strains of Streptococcus pneumoniae and 144 strains of Haemophilus influenzae isolated from respiratory organs in the First Department of Internal Medicine, Shinshu University, and affiliated hospitals between January 2000 and February 2001. The following results were obtained. 1. Fifty-one (47.2%), 56 (51.9%), and 1 (0.9%) of 108 strains of S. pneumoniae were classified as penicillin-susceptible S. pneumoniae (PSSP), penicillin-intermediate S. pneumoniae (PISP), and penicillin-resistant S. pneumoniae (PRSP), respectively. 2. Three carbapenems had potent antimicrobial activity against PISP and PRSP. Furthermore, none of the strains were highly resistant (MIC > 2 micrograms/ml) to benzylpenicillin, ampicillin (ABPC), sulbactam/ampicillin (SBT/ABPC), cefotaxime (CTX), or cefepime (CFPM). 3. Eleven (7.6%) and 6 (4.2%) of 144 strains of H. influenzae were classified as beta-lactamase-producing ABPC-resistant strains and beta-lactamase negative ABPC-resistant H. influenzae (BLNAR), respectively. Levofloxacin, sulfamethoxazole/trimethoprim, and meropenem had potent antimicrobial activity against these resistant strains. 4. BLNAR strains were more highly resistant to CTX, CFPM, SBT/ABPC, and cefaclor than beta-lactamaseproducing strains. 5. In our surveillance study regarding clinical isolates of S. pneumoniae and H. influenzae from respiratory organs in Nagano prefecture, there were regional differences in the isolation rate and antimicrobial susceptibility. The isolation rates of resistant strains were lower than those reported in a nationwide survey.     

Antimicrobial effects of drugs against multidrug-resistant Pseudomonas aeruginosa

We evaluated the effects of antimicrobial drugs on four strains of Pseudomonas aeruginosa that are resistant to eight widely used antipseudomonal drugs (piperacillin, piperacillin-tazobactam, imipenem, meropenem, ceftazidime, aztreonam, amikacin, ciprofloxacin) and colistin. In the killing test, colistin (2 microg/ml) was the most effective, followed by aztreonam (48 microg/ml), piperacillin-tazobactam (192-4 microg/ml), piperacillin (192 microg/ml), and a three drug combination of azetreonam (16 microg/ml), ceftazidime (16 microg/ml), and amikacin (4 microg/ml). Six hours after drug addition, colistin (2 microg/ml), aztreonam (48 microg/ml), piperacillin-tazobactam (192-4 microg/ml), piperacillin (192 microg/ml), and the above three drug combination had bacteriostatic effects on all four strains. Colistin, three time breakpoint of aztreonam, piperacillin, or piperacillin-tazobactam, and the three drug combination of aztreonam, ceftazidime, and amikacin were effective in vitro.     

铜绿假单胞菌的耐药趋势变化及治疗进展

摘要：铜绿假单胞菌是医院获得性感染的重要条件致病菌,具有易定植、易变异和多耐药的特点。下呼吸道因生理结构特殊而成为多重耐药铜绿假单胞菌感染的频发部位,往往难以治疗,导致医疗费用乃至院内死亡率增加。本文汇总了国内外细菌监测计划数据,分析近5年铜绿假单胞菌的检出率及耐药变化情况。在此基础上,分别归纳院内肺炎治疗指南和专家共识的用药建议、治疗研究进展和未来发展趋势,为临床制定抗感染决策以及今后抗菌治疗探索方向提供有价值的参考。     

Biofilm formation and serum susceptibility in Pseudomonas aeruginosa

Pseudomonas aeruginosa (P. aeruginosa) is one of the most important opportunistic pathogens. The pathogenicity of P. aeruginosa has been associated with multiple bacterial virulence factors. The aim of this study was to evaluate the association between P. aeruginosa strains obtained from various clinical samples and resistance to antibiotics and pathogenicity factors, such as resistance to serum bactericidal activity and biofilm formation. This study included 121 P. aeruginosa strains isolated from clinical samples; 65 of the isolated P. aeruginosa strains were carbapenem-resistant, and 56 were carbapenem-sensitive. Carbapenem-resistant P. aeruginosa strains were more often resistant to the majority of tested antibiotics, compared to carbapenem-sensitive strains. We did not find any statistically significant difference between resistance to carbapenems and serum resistance and ability of tested P. aeruginosa strains to produce biofilms. Carbapenem-resistant P. aeruginosa strains were recovered from the urinary tract significantly more often (75.0%) than carbapenem-sensitive P. aeruginosa strains (25.0%). Carbapenem-sensitive P. aeruginosa strains were recovered significantly more often from the respiratory tract than carbapenem-resistant strains, 60.0% and 40.0%, respectively. All the P. aeruginosa strains recovered from blood were serum-resistant. P. aeruginosa strains recovered from the respiratory tract and wounds were significantly frequently serum sensitive, 95.6% and 56.6%, respectively. We did not find any differences in biofilm production among the P. aeruginosa strains recovered from different sources.     

Characteristics of Pseudomonas aeruginosa isolated from skin infections

From January 1995 to June 2000, 19 Pseudomonas aeruginosa were detected in 19 cases of infectious skin diseases. Coagulase-negative staphylococci coexisted with P. aeruginosa in 10 cases and P. aeruginosa was also often associated with Enterococcus sp., Staphylococcus aureus, Streptococcus sp. or other species. Twelve cases carried P. aeruginosa more predominantly than the other species. Some coagulase-negative staphylococci, Enterococcus sp., S. aureus and Streptococcus sp. were also predominant. The frequency of predominant P. aeruginosa was significantly higher in secondary infections due to ulcers and decubitus than in secondary infections due to other skin diseases. P. aeruginosa was also often detected in the legs and feet, but not in the trunk. This organism showed high sensitivities to antibiotics, except minocycline. No significant differences in sensitivity or resistance to antibiotics were found between P. aeruginosa when detected as the predominant or single strain and this microorganism when detected as the non-predominant strain. Thus, the detection of P. aeruginosa important in choosing the appropriate antibiotics to be used and this is sometimes influenced by the patient's condition.     

Antimicrobial susceptibility of uncommonly isolated non-enteric Gram-negative bacilli

The frequency of occurrence and antimicrobial susceptibility patterns of 3059 non-enteric Gram-negative bacilli (NGB), other than Pseudomonas aeruginosa and Acinetobacter spp., consecutively collected as part of the SENTRY Antimicrobial Surveillance Program (1997-2003) were reviewed. During this period, a total of 221,084 bacterial isolates were collected from several clinical specimens worldwide, including 25,305 (11.5%) NGB. Acinetobacter spp. and P. aeruginosa accounted for 82.7% of the NGB isolates and have been excluded from this analysis. The antimicrobial susceptibility results of 3509 strains from 13 species/genera have been analysed in this review. The isolates were tested by reference broth microdilution methods in three central laboratories using common reagents and procedures. More than 30 antimicrobial agents were tested and the results for the 18 most active compounds are reported here. Stenotrophomonas maltophilia (2076 strains; 59.2%) was the most frequently isolated pathogen in this group, followed by Aeromonas spp. (385 strain; 11.0%), Burkholderia cepacia (269 strains; 7.7%), Pseudomonas fluorescens/putida (253 strains; 7.2%) and Alcaligenes spp. (236 strains; 6.7%). All other species/genera accounted for less than 3% of the isolates analysed. The antimicrobial agents with the most consistent activity against the NGB evaluated in the present study were the newer fluoroquinolones gatifloxacin and levofloxacin with 84.1 and 84.9% susceptibility overall. Trimethoprim/sulphamethoxazole was active against 85.3% of the isolates tested, but showed reduced activity against P. fluorescens/putida (22.1% susceptibility). Antimicrobial susceptibility varied significantly between species/genera and the geographical regions evaluated. Thus, proper identification and quantitative susceptibility testing will be required for the treatment of NGB infections. Extensive worldwide surveillance programmes remain extremely important to guide empirical antimicrobial therapy for rarely isolated pathogens and also for pathogens that are not routinely tested due to the lack of standardised susceptibility testing methods.     

Antimicrobial susceptibility of corynebacteria isolated from ewe''s mastitis

The antimicrobial susceptibility of 50 coryneform isolates from subclinical mastitis in sheep was evaluated. Arcanobacterium pyogenes (five isolates) had a susceptibility pattern distinct from the Corynebacterium species tested. The Corynebacterium isolates could be divided in two groups according to the MIC values for ciprofloxacin. Their antimicrobial susceptibility was usually unpredictable and consequently antimicrobial susceptibility tests are necessary for clinical and epidemiological purposes.     

Antimicrobial susceptibility of Listeria monocytogenes isolated from meningoencephalitis in sheep

The antimicrobial susceptibility to different antimicrobial agents of 41 Listeria monocytogenes strains isolated from sheep with meningoencephalitis and from feedstuff was tested by both microdilution and disk diffusion methods. Both sets of isolates of L. monocytogenes were susceptible to penicillin G, amoxicillin, cephalothin, erythromycin, vancomycin, rifampicin, gentamicin, kanamycin, trimethoprim, sulfisoxazole, chloramphenicol and ciprofloxacin, but resistant to tetracycline and doxycycline (7.3 and 4.9%, respectively). Tetracycline was the most frequent resistance trait in L. monocytogenes strains of animal origin. Four strains (9.8%) also exhibited reduced susceptibility (MIC 4 mg/l) to doxycycline suggesting the need of surveillance studies to monitor the antimicrobial resistance of Listeria strains of animal origin.     

Pseudomonas aeruginosa susceptibility in a university hospital: recognition and treatment

Pseudomonas aeruginosa continues to be a leading cause of nosocomial bacteremia and other serious, often life-threatening infections. The incidence of P. aeruginosa infection appears to be increasing. The resilience of Pseudomonas in the hospital environment, its endogenous virulence factors, and its current level of resistance to antimicrobials make it a formidable pathogen, particularly in a compromised host. Despite the availability of several effective antipseudomonal antibiotics, infections caused by this pathogen are still associated with significant morbidity and mortality. Early recognition and prompt intervention with appropriate antimicrobial agents are vital to successful management. Combination therapy with an aminoglycoside and an extended-spectrum penicillin or cephalosporin is recommended in the initial management of suspected or documented P. aeruginosa infections.     

Isolation-frequency and antibiotic susceptibility of Streptococcus pneumoniae, Haemophilus influenzae, and Pseudomonas aeruginosa isolated in regional core hospitals in the Nagaoka district of Niigata Prefecture (changes for 3 years)

We measured MICs of various antimicrobial agents against Streptococcus pneumoniae, Haemophilus influenzae, and Pseudomonas aeruginosa isolated in the Nagaoka district of Niigata Prefecture in 2000 (March-May), 2001 (January-May), and 2002 (March-May). S. pneumoniae: Fifty-six strains were isolated in 2000, 119 strains in 2001, and 88 strains in 2002. In 2000, 2001, and 2002, 24 strains (42.9%), 58 strains (48.7%), and 40 strains (45.5%), respectively, were penicillin-intermediate S. pneumoniae (PISP), and 4 strains (7.1%), 12 strains (10.1%), and 7 strains (8.0%), respectively, were penicillin-resistant S. pneumoniae (PRSP). Carbapenems had the most excellent antimicrobial activity, followed by penicillin G, against penicillin-susceptible S. pneumoniae (PSSP), PISP, and PRSP. H. influenzae: Seventy-six strains were isolated in 2000, 154 strains in 2001, and 91 strains in 2002. In 2000, 2001, and 2002, 6 strains (7.9%), 8 strains (5.2%), and 7 strains (7.7%), respectively, were beta-lactamase-producing ampicillin (ABPC)-resistant strains (MIC > or = 2 micrograms/ml), showing no increase, and 14 strains (18.4%), 70 strains (45.5%), and 31 strains (34.1%), respectively, were beta-lactamase-non-producing ABPC-resistant strains (MIC > or = 2 micrograms/ml), showing a slight increase. Ceftriaxon, meropenem (MEPM), and levofloxacin had excellent antimicrobial activity against these resistant strains. P. aeruginosa: In 2000, 2001, and 2002, 135, 74, and 91 strains, respectively, were isolated, and 14 strains (10.4%), 17 strains (23.0%), and 24 strains (26.4%), respectively, were imipenem-resistant (MIC > or = 16 micrograms/ml), showing a slight increase. MEPM, biapenem, and ciprofloxacin had excellent antimicrobial activity against P. aeruginosa.     

Characterization of a novel gene related to antibiotic susceptibility in Pseudomonas aeruginosa

Pseudomonas aeruginosa is a human pathogen with increased intrinsic resistance to a large number of antibiotics used in clinical therapy. Therefore, understanding the mechanisms of resistance and developing therapy alternatives for P. aeruginosa are of profound importance. Previous work from our laboratory demonstrated that several mutants have isolated with altered expression of the phzA1B1C1D1E1F1G1 (phzA1) operon in the presence of sub-inhibitory concentrations (SICs) of tetracycline (TET). The present study investigates the roles of the PA0011 gene in mediating phzA1 expression at SIC of TET. The PA0011 gene encodes 2-OH-lauroytransferase by controlling the synthesis of the cell envelope and the outer membrane. We found that the PA0011 mutant strain was susceptible to several different antibiotics and environmental stresses. Complementation in the PA0011 mutant restored these phenotypes to wild-type levels. In addition, expression of the PA0011 gene, as monitored through a luciferase reporter, is increased at SICs of antibiotics. Indeed, the expression of the PA0011 gene increased about threefold in pqsR and pqsH mutants compared with the wild-type PAO1. However, the PA0011 gene negatively regulates the quorum sensing (QS) system. Taken together, these data suggest that PA0011 is involved in susceptibility to antimicrobial agents in P. aeruginosa, and that its susceptibility effect maybe partly dependent on increased QS expression.     

Antimicrobial susceptibility of potentially pathogenic halophilic vibrios isolated from seafood

Susceptibility patterns to 27 antimicrobial agents and beta-lactamase production were investigated in potentially pathogenic halophilic vibrios from seafood. The effect of salinity on the response to the drugs in vitro was also studied. All isolates were uniformly sensitive to choramphenicol, imipenem, meropenem but resistant to lincomycin. All were highly sensitive to oxolinic acid, trimethoprim-sulphamethoxazole, doxycycline, flumequine, cefotaxime, nalidixic acid and ciprofloxacin. Some strains of V. harveyi, V. alginolyticus and V. parahaemolyticus apparently had mechanisms of resistance to several beta-lactam antibiotics other than by the production of beta-lactamases. Sixty-nine strains produced penicillinase but a low correlation between beta-lactamase activity and resistance to beta-lactam antibiotics was noted. The salt concentration affected the in vitro susceptibility of halophilic vibrios and the effect of salinity depended on both the individual strains and the antimicrobial tested.     

Antimicrobial susceptibility of Neisseria meningitidis isolated from 1975-1979

During the period 1975 to 1979, 88 isolates of Neisseria meningitidis from cerebrospinal fluid (CSF), 28 isolates from blood, and 89 isolates from other sources were serogrouped and tested for their susceptibility to sulphadiazine, penicillin, minocycline and rifampin. Prior to 1979, isolates from CSF or blood were predominantly serogroup B. In the sample tested, the prevalence of this serogroup decreased while the prevalence of serogroup A isolates increased, until in 1979 this was the predominant serogroup. From 1975, the incidence of sulphonamide-resistance in the serogroup B isolates from CSF or blood decreased. However, all serogroup A isolates from these sources, except the first one tested, were sulphonamide-resistant. The 89 isolates from other sources remained predominantly sulphonamide-sensitive serogroup B. All isolates were sensitive to penicillin, minocycline and rifampin.     

Surveillance on Pseudomonas aeruginosa isolated in Gifu prefecture (2004)

We analyzed Pseudomonas aeruginosa isolates in Gifu prefecture between September and October 2004. We conducted antimicrobial susceptibility test for 266 strains isolated from 8 medical institutes and 1 clinical laboratory, based on broth microdilution method. The MIC50 and MIC90 of piperacillin, amikacin, imipenem, and ciprofloxacin were 4 and 64, 4 and 8, 1 and 16, 0.25 and 8 microg/mL, respectively. The strains isolated from urine had higher MIC level in comparison with from sputum, which was remarkable in penicillins, cephalosporins and fluoroquinolones. We isolated 7 strains of multi-drug resistant Pseudomonas aeruginosa (MDRP), in which 3 strains showed under 16 microg/mL in MIC against anti-MRSA (methicillin-resistant Staphylococcus aureus) drug arbekacin. Continuous surveillance would be needed for antimicrobial resistance on P. aeruginosa in Gifu prefecture.