ABSTRACT
OBJECTIVE To analyze the drug-resistance of Enterobacter cloacae isolated from clinic in the past two years.METHODS The drug-resistance by K-B method,and to perform 3-D test to detect AmpC ?-lactamase and ESBLs were detected.RESULTS One hundred and six strains of E.cloacae was detected.Burn department were the wards which had the highest detection rate.Sputum,wound,bile and drainage fluid had the highest positive rate.Sensitivity test results showed that the resistance rate to penicilins,Ⅰ,Ⅱ-generation cephalosporins and cefoxitin of E.cloacae was the highest,and the resistance rate to the third,and fourth-generation cephalosporins was 24.5-50.9%.The detection rate of ESBLs and AmpC was 27.4% and 40.6%,respectively.Twenty three strains produced both of them.CONCLUSIONS The detection rate and drug resistance of E.cloacae are increasing severely.Laboratory should pay more attention to their detections and surveillance so as to control hospital infection of E.cloacae.
ABSTRACT
OBJECTIVE To analyze the distribution and drug-resistance of Klebsiella pneumoniae isolated from clinic in the past two years to help doctors to use antibiotic reasonably.METHODS To detect the drug-resistance of 470 strains of K.pneumoniae to 15 kinds of antimicrobial agents were detected by K-B method,and the AmpC ?-lactamase and ESBLs were detected through the way of 3-D test.RESULTS ICU and burn department were found where had the highest isolation rate,and sputum and wound that had the highest detection rate.Sensitivity test results showed that the resistance rate of K.pneumoniae to penicillins,first and second-generation cepholosporins,fluoroquinolones and sulfamethoxazole compound was high(51.1-88.3%),and resistance rate to the third and fourth-generation cephalosporins was high,too(32.6-40.4%).All strains were sensitive to imipenem,but two of them were resistant to meropenem.ESBLs were found in 152 strains,the detection rate was 32.3%,AmpC was found in 29 strains,the detection rate was 6.2%.Both of them were found out in 21 strains.CONCLUSIONS The lower respiratory tract infection is the most common one.The ICU and wound ward are the high-risk places ward of infection.Detection rate and drug resistance are increasingly severe,clinic and laboratory should make concerted efforts to reduce nosocomial infection and strengthen information feedback.
ABSTRACT
OBJECTIVE To explore the clinical distribution characteristics and the drug-resistance of AmpC-producing Enterobacter cloacae in ICU. METHODS Seventy-eight strains of E. cloacae were isolated in ICU from Jan 2005 to Jan 2006 and antimicrocal sensitivities were determined by K-B method. RESULTS Among 78 E. cloacal strains derived from the lower respiratory tract and wound secretion,32 (41.0%) were AmpC producing and were sensitive to imipenem (96.9%) and merapenem (93.8%). CONCLUSIONS AmpC-producing E. cloacae is one of the main pathgens of nosocomial infection in ICU,imipenem and merapenem are the first choice to treat the infection.
ABSTRACT
OBJECTIVE To analyze the drug-resistance of Escherichia coli isolated from clinic in the past two years. METHODS The drug-resistance to 19 kinds of antimicrobial agents of 435 E. coli strains was detected by K-B method. 3-D test was performed to detect AmpC ?-lactamase and Extended-spectrum ?-lactamases(ESBLs). RESULTS It showed that the strains from cervical secretions, urine, throat swab and lochia specimens had the highest positive rate. Sensitivity test results showed that the resistance rate to ampicillin, aztreonam, sulfamethoxazole/trimethoprims and quinolones was high (49.23-84.10%), and resistance rate to the third, and fourth-generation cephalosporins was high too(31.35-46.80%). Strains that resistant to imipenem and meropenem were not detected out and they had a high sensitivity rate (93.38%), to cefoperazone/sulbactam. Detection rate of ESBLs and AmpC was 32.67% and 5.52%, respectively. Nineteen srtains produced both of them and 6 srtains produced AmpC only. CONCLUSIONS The detection rate and drug resistance are increasingly severe. Clinic and laboratory should make efforts to reduce hospital infection and dissemination of drug-resistant strains.
ABSTRACT
OBJECTIVE To investigate the resistance phenotype and clinical feature of super extended spectrum ?-lactamases(SSBLs) producing Escherichia coli in order to provide reference for the clinical application of drugs.METHODS Totally 945 strains of ESBLs producing E.coli collected from Jan 2003 to Jun 2007 were identified by API microbiological assay system.Susceptbility tests were performed by K-B methods.Improved three-dimensional tests were adopted to test ESBLs and AmpC lactamase.Test data were analyzed statistically by WHONET 5.3 software.RESULTS From them eighteren strains of SSBLs producers were detected.Between the positive for ESBLs strains and the negative strains,there were some significant differences in the antimicrobial resistance(P
ABSTRACT
OBJECTIVE To study the resistant phenotype and molecular biology character of 106 clinical isolates of Enterobacteriaceae.METHODS The 106 clinical isolates of Enterobacteriaceae were studied by agar dilution method,mutiplex PCR and DNA sequencing methods were used in further study.RESULTS The AmpC ?-lactamase was detected in 35 isolates of Enterobacteriaceae(accounted for 33.02%),34 of 35 AmpC-producing isolates were resistant to cefoxitin,1 of 35 AmpC-producing isolates was intermediate-susceptible to cefoxitin,the susceptibility to cefepime and imipenem was 68.50% and 97.10%,respectively.CONCLUSIONS A new plasmid mediated AmpC ?-lactamase is detected in one isolate of Enterobacteriaceae.The antibiotic resistance is closely associated with antibiotic resistance genes.
ABSTRACT
OBJECTIVE To analyze the resistance of Enterobacter cloacae AmpC ?-lactamase with/without being induced by imipenem(IMP),cefepime(FEP),ceftriaxone(CRO) and aztreonam(ATM).The ampD genes of mutant strains were sequenced. METHODS Five wild type strains and 5 hyper-inducible type strains of E.cloacae were selected and induced by the tested antibiotics in vitro.At the same time,antibiotic susceptibility tests,3-D test,isoelectric focusing(IEF) and inhibit experiment were detected to identify hyper-producing AmpC ?-lactamase.ampD Gene sequencing was preformed in part of mutant strains. RESULTS There wasn′t obvious alteration in MIC with IMP,FEP,CRO and ATM for wild type strains whether they were induced or not.But,for the hyper-inducible type,there was apparent increasing in MIC after antibiotics inducing,especially CRO and ATM,up to 10.7-128 times.The DNA sequences analysis in the mutation strains showed there existed the replacement of the single base in multiple sites,and a few sites of amino acid were altered. CONCLUSIONS Mutant sites in ampD gene sequences are identical even though antibiotics as inducer are different.
ABSTRACT
OBJECTIVE To explore production of ?-lactamase induced by antibiotics in Pseudomonas aeruginosa biofilm and planktonic bacteria.METHODS In vitro models of P.aeruginosa biofilm were built up.The planktonic bacteria and P.aeruginosa biofilms were exposed to different concentrations of imipenem and ceftazidime.The quantitative analysis of ?-lactamase was undertaken.The class of ?-lactamase was verified by modified cefoxitin three-dimensional test.RESULTS Both P.aeruginosa biofilm and planktonic bacteria showed significant ?-lactamase activity in the presence of antibiotics.The maximal ?-lactamase activities of both were significantly different with the statistic method of test(P
ABSTRACT
BACKGROUND: A rapid increase of antimicrobial-resistant bacteria has become a serious problem in many countries. The aim of this study was to determine the prevalence of resistance among frequently isolated gram-positive and -negative bacteria in Korea. METHODS: Data of routine antimicrobial susceptibility test for medically important bacteria, isolated during 3 months of 2002, were collected from 12 university and 1 commercial laboratories in Korea. RESULTS: The proportions of methicillin-resistant Staphylococcus aureus (MRSA) were 60-88%, but vancomycin-resistant S. aureus was not detected. Among the Enterococcus faecium isolates, the resistance rate to vancomycin was 29%. The resistance rates of Escherichia coli and Klebsiella pneumoniae: 11% and 24% to cefotaxime, respectively, and 12% and 21% to cefoxitin, respectively. The resistance rates of Citrobacter freundii, Enterobacter cloacae, and Serratia marcescens: 28%, 34% and 21% to cefotaxime, respectively, <1%, 8% and 14% to cefepime, respectively. The resistance rates of Acinetobacter baumannii and Pseudomonas aeruginosa were: 65% and 37% to piperacillin, 64% and 19% to ceftazidime, 13% and 20% to imipenem, respectively. The resistant rates varied according to the hospital size. The resistance rates were generally higher among the isolates in the hospitals with more than 1,000 beds. The rates of penicillin-nonsusceptible Streptococcus pneumoniae were 58-90%. Among the Haemophilus influenzae isolates, 55-68% were resistant to ampicillin. CONCLUSIONS: Antimicrobial resistant strains were prevalent among the medically important clinical isolates, especially, MRSA, vancomycin-resistant enterococci, extended-spectrum -lactamase- or AmpC -lactamase-producing E. coli and K. pneumoniae, third generation cephalosporin-resistant C. freundii, E. cloacae and S. marcescens, imipenem-resistant A. baumannii and P. aeruginosa, penicillin-nonsusceptible S. pneumoniae and ampicillin-resistant H. influenzae. The antimicrobial resistance has become a serious problem in Korea.
Subject(s)
Acinetobacter baumannii , Ampicillin , Bacteria , Cefotaxime , Cefoxitin , Ceftazidime , Citrobacter freundii , Cloaca , Enterobacter cloacae , Enterococcus faecium , Escherichia coli , Haemophilus influenzae , Health Facility Size , Imipenem , Influenza, Human , Klebsiella pneumoniae , Korea , Methicillin-Resistant Staphylococcus aureus , Piperacillin , Pneumonia , Prevalence , Pseudomonas aeruginosa , Serratia marcescens , Streptococcus pneumoniae , VancomycinABSTRACT
BACKGROUND: Plasmid-mediated AmpC beta-lactamases (PABL) are cephalosporinases that confer resistance to a wide variety of beta-lactam drugs and that may thereby create serious therapeutic problems. The PABL-producing organisms are a major concern in nosocomial infections and should there-fore be monitored in surveillance studies. Although reported with increasing frequency in Korea, the occurrence and genotypic distributions of PABL in Escherichia coli and Klebsiella pneumoniae remain unknown. METHODS: We tested a total of 911 consecutive, nonduplicate isolates of E. coli and K. pneumoniae at 12 university hospitals and a commercial laboratory in Korea. Antimicrobial susceptibilities were tested using the disk diffusion method. PABL production was determined by the modified Hodge test and multiplex PCR. The PCR differentiated the six PABL-specific families in E. coli and K. pneumoniae. RESULTS: Overall, 110 (12.1%) yielded cefoxitin non-susceptible isolates and that 28 (3.1%) demonstrated PABL producers by multiplex PCR. Based on the species, of 544 E. coli and 367 K. pneumoniae isolates tested, 8 (1.5%) and 20 (5.4%), respectively, demonstrated PABL producers. The genotypes of PCR amplification showed that the MOX, DHA, and CIT family were harbored by 4, 2, and 2 of 8 PABL-producing E. coli, and the DHA, MOX, and EBC family were harbored by 13, 6, and 1 of 20 PABL-producing K. pneumoniae isolates, respectively. CONCLUSIONS: These data confirm that the occurrence of PABL-producing E. coli and K. pneumoniae is relatively high and the kinds of genotypes are variously distributed in Korea.