title: Molecular characterization of extended-spectrum beta-lactamases produced by clinical isolates of Klebsiella pneumoniae and Escherichia coli from a Korean nationwide survey.
abstract: 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.
authors.affiliation: Department of Biological Science, Myongji University, San 38-2 Namdong, Yongin, Kyunggido 449-728, South Korea.
authors.forename: Seok Hoon
authors.initials: SH
authors.lastname: Jeong
authors.forename: Il Kwon
authors.initials: IK
authors.lastname: Bae
authors.forename: Jung Hun
authors.initials: JH
authors.lastname: Lee
authors.forename: Seung Ghyu
authors.initials: SG
authors.lastname: Sohn
authors.forename: Geun Ho
authors.initials: GH
authors.lastname: Kang
authors.forename: Ghil Ja
authors.initials: GJ
authors.lastname: Jeon
authors.forename: Young Ho
authors.initials: YH
authors.lastname: Kim
authors.forename: Byeong Chul
authors.initials: BC
authors.lastname: Jeong
authors.forename: Sang Hee
authors.initials: SH
authors.lastname: Lee
mesh_terms: 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*
chemical_list: D001618:beta-Lactamases