Genotype analysis of ESBLs-producing Klebsiella pneumoniae isolates / 中国感染与化疗杂志

Objective To identify the genotypes of ESBLs-producing Klebsiella pneumoniae isolates from the First Affiliated Hospital,Shantou University Medical College.Methods The MICs of 10 antibiotics were determined by agar-dilution against the clinical isolates of ESBLs-producing K.pneumoniae.PCR were performed with specific primers for blaTEM,blaSHV, blaCTX-M and blaOXA respectively.PCR products were cloned and sequenced.Results The results of PCR showed that a- mong the 83 strains of ESBLs-producing K.pneumoniae,75 were positive for blaTEM,41 positive for blaSHV,25 poitive for blaCTX-M,9 positive for hlaOXA.Three genotypes were found in 13 strains(15.7%),2 genotypes in 59 strains (71.1%) and single genotype in only 11 strains(13.2%).The genes of CTX-M-3,TEM-1 and SHV were found co-existent in 9 strains. The strains carrying 2 or 3 ESBL genes were more resistant to antibiotics than those carrying only 1 ESBL gene.Conclusions The genotypes of ESBLs-producing Klebsiella pneumoniae in this hospital are blaTEM,blaSHV,blaCTX-M and blaOXA. Most strains carry 2 or 3 ESBL genes.

Prevalence of CTX-M-type Extended-Spectrum beta-Lactamase-Producing Esherichia coli and Klebsiella pneumoniae Isolates in Korea / 대한임상미생물학회지

BACKGROUND: The aim of this study was to survey the nation wide susceptibilities of Esherichia coli and Klebsiella pneumoniae against cefotaxime and to determine the prevalence of CTX-M-type extended-spectrum beta- lactamases(ESBLs). METHODS: During the period of April to June, 2002, E. coli and K. pneumoniae isolates were collected from 13 hospitals. Antimicrobial susceptibilities to cefotaxime were tested by the disk diffusion method. ESBL production was determined by double disk synergy test. Cefotaxime-resistance of the ESBL-producers was transferred to azide-resistant E. coli J53 by conjugation. MICs of beta- lactam antibiotics were determined by agar dilution method. Searches for blaCTX-M genes were performed by PCR amplication. pIs of beta-lactamases were determined by isoelectric focusing. RESULTS: Ten percents of E. coli and 35 percents of K. pneumoniae isolates among 260 strains of each were intermediate or resistant to cefotaxime. Twenty-three isolates of E. coli and 78 K. pneumoniae isolates showed positive results in the double disk synergy test. One isolate of E. coli and 2 K. pneumoniae isolates harbored blaCTX-M-3 gene, 2 E. coli isolates harbored blaCTX-M-15 gene, and 2 E. coli and 2 K. pneumoniae isolates harbored blaCTX-M-14 gene. CONCLUSION: E. coli and K. pneumoniae isolates producing CTX-M-type ESBLs are not uncommon in Korean hospitals. The spread of CTX-M-type ESBL genes could compromise the future usefulness of 3rd generation cephalosporins and aztreonam for the treatment of E. coli and K. pneumoniae infections.

Prevalence of CTX-M-type Extended-Spectrum beta-Lactamase-Producing Escherichia coli and Klebsiella pneumoniae Isolates in Korea, 2003 / 대한임상미생물학회지

BACKGROUND: The aims of this study were to survey nationwide susceptibilities of Escherichia coli and Klebsiella pneumoniae isolates against cefotaxime and to determine the prevalences of CTX-Mtype extended-spectrum beta-lactamases(ESBLs). METHODS: During the period of February to July, 2003, E. coli and K. pneumoniae isolates were collected from 12 hospitals. Antimicrobial susceptibilities to cefotaxime were tested by the disk diffusion method. ESBL production was determined by the double disk synergy test. Cefotaxime-resistance of the ESBL-producers was transfered to E. coli DH5alphaand E. coli Top10-F by transformation. MICs of beta-lactam antibiotics were determined by the agar dilution method. Searches for blaCTX-M genes was performed by PCR amplication; pIs of beta-lactamases were determined by isoelectric focusing. RESULTS: Among 230 isolates of E. coli and 232 isolates of K. pneumoniae, 27 (11.7%) and 79 (34.1%) were intermediate or resistant to cefotaxime, respectively. Twenty-four (10.4%) isolates of E. coli and 58 (25.0%) K. pneumoniae isolates showed positive results in the double disk synergy test. Three isolates of E. coli and 13 K. pneumoniae isolates harbored blaCTX-M-3 gene, 4 E. coli isolates harbored blaCTX-M-15 gene, and 1 E. coli and 5 K. pneumoniae isolates harbored blaCTX-M-14 gene. CONCLUSION: E. coli and K. pneumoniae isolates producing CTX-M-type ESBLs were not uncommon in Korean hospitals. It is thought that periodical surveys are necessary for inspecting the spread of CTX-M-type ESBL genes are necessary.

Prevalence of CTX-M Extended-spectrum Beta-lactamases in Clinical Isolates of Enterobacteriaceae in Korea

The evolution and dissemination of extended-spectrum beta-lactamases (ESBL) have compromised the clinical use of third-generation cephalosporins worldwide. Although most ESBLs belong to the TEM and SHV beta-lactamase families, the members of CTX-M, a novel ESBL family, are increasing worldwide in Gram-negative bacteria. We examined the prevalence of CTX-M ESBL in clinical isolates of the family Enterobacteriaceae collected from three university hospitals located in three different cities in Korea. Among a total of 603 isolates collected, 163 isolates (27.0%) revealed > or =2 microgram/ ml of MIC against cefotaxime, and 93 isolates (15.4%) produced ESBL confirmed by the double disk synergy test. Among 93 ESBL-producing isolates, blaCTX-M genes were detected in 41 isolates by PCR method and they included 1 isolate of C. freundii, 3 of E. aerogenes, 2 of E. cloacae, 17 of E. coli, 9 of K. pneumoniae, and 9 of S. marcescens. Thus, the overall prevalence of CTX-M ESBL-producing isolates among the family Enterobacteriaceae was 6.8% (41 of 603 isolates) and the proportion of CTX-M-producers among the ESBL-producing isolates was 44.1% (41 of 93 isolates). Further determination of the blaCTX-M subtype by nucleotide sequencing revealed blaCTX-M-3 in 17, blaCTX-M-15 in 11, blaCTX-M-14 in 9, and blaCTX-M-9 in 4 isolates. To our knowledge, this is the first report on the dissemination of CTX-M ESBL among clinical isolates of the family Enterobacteriaceae in Korea.

Prevalence of CTX-M Extended-spectrum Beta-lactamases in Clinical Isolates of Enterobacteriaceae in Korea

The evolution and dissemination of extended-spectrum beta-lactamases (ESBL) have compromised the clinical use of third-generation cephalosporins worldwide. Although most ESBLs belong to the TEM and SHV beta-lactamase families, the members of CTX-M, a novel ESBL family, are increasing worldwide in Gram-negative bacteria. We examined the prevalence of CTX-M ESBL in clinical isolates of the family Enterobacteriaceae collected from three university hospitals located in three different cities in Korea. Among a total of 603 isolates collected, 163 isolates (27.0%) revealed > or =2 microgram/ ml of MIC against cefotaxime, and 93 isolates (15.4%) produced ESBL confirmed by the double disk synergy test. Among 93 ESBL-producing isolates, blaCTX-M genes were detected in 41 isolates by PCR method and they included 1 isolate of C. freundii, 3 of E. aerogenes, 2 of E. cloacae, 17 of E. coli, 9 of K. pneumoniae, and 9 of S. marcescens. Thus, the overall prevalence of CTX-M ESBL-producing isolates among the family Enterobacteriaceae was 6.8% (41 of 603 isolates) and the proportion of CTX-M-producers among the ESBL-producing isolates was 44.1% (41 of 93 isolates). Further determination of the blaCTX-M subtype by nucleotide sequencing revealed blaCTX-M-3 in 17, blaCTX-M-15 in 11, blaCTX-M-14 in 9, and blaCTX-M-9 in 4 isolates. To our knowledge, this is the first report on the dissemination of CTX-M ESBL among clinical isolates of the family Enterobacteriaceae in Korea.