Prevalence of the Extended-Spectrum beta-Lactamase and qnr Genes in Clinical Isolates of Escherichia coli.
10.3343/kjlm.2009.29.3.218
- Author:
Yongjung PARK
1
;
Hyun Kyung KANG
;
Il Kwon BAE
;
Juwon KIM
;
Jae Seok KIM
;
Young UH
;
Seok Hoon JEONG
;
Kyungwon LEE
Author Information
1. Department of Laboratory Medicine and Research Institute of Bacterial Resistance, Yonsei University College of Medicine, Seoul, Korea. kscpjsh@yuhs.ac
- Publication Type:Original Article
- Keywords:
Escherichia coli;
CTX-M ESBL;
qnrA1;
qnrB4
- MeSH:
Disk Diffusion Antimicrobial Tests;
Escherichia coli/*enzymology/genetics/isolation & purification;
Escherichia coli Proteins/classification/*genetics;
Humans;
Inhibitory Concentration 50;
Polymerase Chain Reaction;
beta-Lactamases/biosynthesis/genetics/*metabolism
- From:The Korean Journal of Laboratory Medicine
2009;29(3):218-223
- CountryRepublic of Korea
- Language:English
-
Abstract:
BACKGROUND: This study was performed to investigate the prevalence of qnr genes in clinical isolates of Escherichia coli from Korea that produce extended-spectrum beta-lactamases (ESBLs). METHODS: During the period of May to June 2005, we collected clinical isolates of E. coli that were intermediate or resistant to ceftazidime and/or cefotaxime from 11 Korean hospitals. Antimicrobial susceptibility was determined by the disk diffusion and agar dilution methods. ESBL production was confirmed phenotypically by the double-disk synergy test. ESBL and qnr genes were searched for by PCR amplification, and the PCR products were then subjected to direct sequencing. RESULTS: Double-disk synergy tests were positive in 84.3% (118/140) of ceftazidime- and/or cefotaxime-nonsusceptible E. coli isolates. The most prevalent types of ESBL in E. coli isolates were CTX-M-14 (N=41) and CTX-M-15 (N=58). Other ESBLs were also identified, including CTX-M-3 (N=7), CTX-M-9 (N=8), CTX-M-12 (N=1), CTX-M-57 (N=1), SHV-2a (N=2), SHV-12 (N=17) and TEM-52 (N=4). The qnrA1 and qnrB4 genes were identified in 4 and 7 ESBL-producing isolates, respectively. CONCLUSIONS: CTX-M-type enzymes were the most common type of ESBL in E. coli isolates from Korea, and the qnr genes were not uncommon in ESBL-producing E. coli isolates. Dissemination of E. coli containing both ESBL and qnr genes could compromise the future usefulness of the expanded-spectrum antibiotics for the treatment of infections.
