Molecular characterization of extended-spectrum beta-lactamases produced by clinical isolates of Klebsiella pneumoniae and Escherichia coli from a Korean nationwide survey.
To determine the prevalence and genotypes of extended-spectrum beta-lactamases (ESBLs) among clinical isolates of Klebsiella pneumoniae and Escherichia coli, we performed antibiotic susceptibility testing, pI determination, induction testing, transconjugation, and DNA sequencing analysis. Among the 509 isolates collected from 13 university hospitals in Korea, 39.2% produced ESBLs. ESBL-producing isolates were detected in every region in Korea. A total of 44.6% of the isolates produced both TEM- and SHV-type ESBLs, and 52% of ESBL-producing isolates transferred resistance to ceftazidime by transconjugation. The ESBLs were TEM-19, TEM-20, TEM-52, SHV-2a, SHV-12, and one new variant identified for the first time in Korea, namely, TEM-116. TEM-1 and SHV-12 were by far the most common variants. TEM-1, TEM-116, and SHV-12 showed a high prevalence in K. pneumoniae. Two isolates (E. coli SH16 and K. pneumoniae SV3) produced CMY-1-like beta-lactamases, which play a decisive role in resistance to cefoxitin and cefotetan, as well as TEM-type enzymes (TEM-20 and TEM-52, respectively). Using MIC patterns and DNA sequencing analysis, we postulated a possible evolution scheme among TEM-type beta-lactamases in Korea: from TEM-1 to TEM-19, from TEM-19 to TEM-20, and from TEM-20 to TEM-52.
Jeong
Seok Hoon
SH
Department of Biological Science, Myongji University, San 38-2 Namdong, Yongin, Kyunggido 449-728, South Korea.
Bae
Il Kwon
IK
Lee
Jung Hun
JH
Sohn
Seung Ghyu
SG
Kang
Geun Ho
GH
Jeon
Ghil Ja
GJ
Kim
Young Ho
YH
Jeong
Byeong Chul
BC
Lee
Sang Hee
SH
D004926:Escherichia coli / Q000187:drug effects / Q000201:enzymology*; D005838:Genotype; D006801:Humans; D007711:Klebsiella pneumoniae / Q000187:drug effects / Q000201:enzymology*; D008826:Microbial Sensitivity Tests; D001618:beta-Lactamases / Q000235:genetics*
D001618:beta-Lactamases