Ambler class A extended-spectrum β-lactamase 생성 Escherichia coli와 Klebsiella pneumoniae의 국내 분리 현황

Abstract

Background: The aim of this study is to determine the nationwide prevalence of Ambler class A extended-spectrum β-lactamase (ESBL)-producing Escherichia coli and Klebsiella pneumoniae and to characterize genotypes of ESBLs.

Methods: During the period of February through July, 2003, E. coli and K. pneumoniae isolates were collected from 12 hospitals in Korea. Antimicrobial susceptibilities were tested by disk diffusion method, and ESBL-production was determined by the double-disk synergy test. MICs of β-lactam antibiotics were tested by agar dilution method. Searches for blaTEM, blaSHV, blaCTX-M, blaPER-1, bla-VEB, blaIBC, blaGES and blaTLA genes were performed by PCR amplification, and the genotypes of ESBLs were determined by direct nucleotide sequence analysis of amplified products.

Results: Resistance rates of E. coli (n=246) and K. pneumoniae (n=239) isolates to ceftazidime were 8.5% and 20.1%, respectively. Most prevalent Ambler class A ESBL genotypes in E. coli isolates were blaCTX-M-15 (n=4) and blaCTX-M-3 (n=3), and each of blaCTX-M-14, blaSHV-12, and blaTEM-52 gene was also found in one isolate. Most prevalent ESBL genotypes in K. pneumoniae were blaSHV-12 (n=30) and blaCTX-M-3 (n=13), and blaCTX-M-14 (n=5). blaSHV-2a (n=3), blaSHV-5 (n=2), blaTEM-52 (n=1), blaGES-3 (n=2) genes were also found.

Conclusion: CTX-M-type ESBL-producing E. coli and K. pneumoniae isolates are spreading, and a GES-type ESBL has emerged in Korea.