title: Investigation of extended-spectrum beta-lactamases produced by clinical isolates of Klebsiella pneumoniae and Escherichia coli in Korea.
abstract: OBJECTIVE
  Isolates obtained from various regions in Korea in 2002 were identified and their susceptibility to extended-spectrum cephalosporins, monobactams and/or cephamycins was studied along with any production of extended-spectrum beta-lactamases (ESBLs).
  
  
  RESULTS
  Bacteria identified by the conventional techniques and Vitek GNI card were Klebsiella pneumoniae and Escherichia coli. Using disk diffusion and double-disk synergy tests, we found that 39.2% of strains produced ESBLs. About 52% of isolates transferred resistance to ceftazidime by conjugation. Banding patterns of PCR amplification with the designed primers showed that 837- and 259-bp fragments specific to bla(TEM) genes were amplified in 63.3% of strains. 929- and 231-bp fragments (bla(SHV)), 847- and 520-bp fragments (bla(CMY)), 597- and 858-bp fragments (bla(CTX-M)) were amplified in 61.5, 17.3 and 7.7% of strains respectively. About 51.9% of strains contained more than two types of beta-lactamase genes. Especially, one strain contained bla(TEM), bla(CMY) and bla(CTX-M) genes.
  
  
  CONCLUSIONS
  Resistance mechanisms to beta-lactams, comprising mostly ESBL production, lead to the resistance against even recently developed beta-lactams in enterobacteria, which is now a serious threat to antibiotic therapy. The high prevalence of bla(CMY) genes and multidrug-resistant genes may also make therapeutic failure and lack of eradiation of these strains by extended-spectrum cephalosporins or cephamycins.
authors.affiliation: Department of Clinical Pathology, Kosin University College of Medicine, Pusan, South Korea.
authors.forename: S H
authors.initials: SH
authors.lastname: Jeong
authors.forename: I K
authors.initials: IK
authors.lastname: Bae
authors.forename: S B
authors.initials: SB
authors.lastname: Kwon
authors.forename: J H
authors.initials: JH
authors.lastname: Lee
authors.forename: H I
authors.initials: HI
authors.lastname: Jung
authors.forename: J S
authors.initials: JS
authors.lastname: Song
authors.forename: B C
authors.initials: BC
authors.lastname: Jeong
authors.forename: S-J
authors.initials: SJ
authors.lastname: Kim
authors.forename: S H
authors.initials: SH
authors.lastname: Lee
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D002511:Cephalosporins / Q000494:pharmacology; D024881:Drug Resistance, Bacterial; D004926:Escherichia coli / Q000145:classification / Q000187:drug effects / Q000201:enzymology* / Q000235:genetics; D004927:Escherichia coli Infections / Q000453:epidemiology / Q000382:microbiology; D006801:Humans; D007710:Klebsiella Infections / Q000453:epidemiology / Q000382:microbiology; D007711:Klebsiella pneumoniae / Q000145:classification / Q000187:drug effects / Q000201:enzymology* / Q000235:genetics; D007723:Korea / Q000453:epidemiology; D008826:Microbial Sensitivity Tests; D016133:Polymerase Chain Reaction; D001618:beta-Lactamases / Q000378:metabolism*; D047090:beta-Lactams / Q000494:pharmacology*
chemical_list: D000900:Anti-Bacterial Agents; D002511:Cephalosporins; D047090:beta-Lactams; D001618:beta-Lactamases