Prevalence and Mechanism of Third-Generation Cephalosporins-Resistant Escherichia coli and Klebsiella pneumoniae Strains Isolated from Clinical Specimen.
- Author:
Jeong Man KIM
1
;
Seok Hoon JEONG
;
Sang Hee LEE
;
Ji Hye KIM
;
Bit Na KIM
;
Jong Chul KIM
Author Information
1. Department of Clinical Pathology, Dong-A University College of Medicine, Korea.
- Publication Type:Original Article
- Keywords:
Escherichia coli;
Klebsiella pneumoniae;
Third-generation cephalosporins;
blaTEM;
blaSHV;
blaCMY
- MeSH:
Agar;
Base Sequence;
beta-Lactamases;
Busan;
Cefotaxime;
Cephalosporins;
Cephamycins;
Diffusion;
Escherichia coli*;
Escherichia*;
Humans;
Incidence;
Klebsiella pneumoniae*;
Klebsiella*;
Korea;
Pneumonia;
Polymerase Chain Reaction;
Prevalence*;
Tertiary Healthcare
- From:Korean Journal of Clinical Microbiology
2002;5(1):6-14
- CountryRepublic of Korea
- Language:Korean
-
Abstract:
BACKGROUND: Among Gram-negative pathogens in Korea, the incidence of resistance to thirdgeneration cephalosporins is becoming an ever-increasing problem. This study was designed to determine the prevalence of third-generation cephalosporins-resistant Escherichia coli and Klebsiella pneumoniae isolates from patients in a tertiary care hospital in Busan, Korea, and to characterize the mechanism of resistance. METHODS: A total of 710 E. coli and 237 K. pneumoniae non-duplicate isolates were collected from patients in Kosin Medical Center in 1999. Antimicrobial susceptibilities were tested by the disk diffusion method. Extended-spectrum beta-lactamase (ESBL) production was determined by the double disk synergy test. MICs were determined by the agar dilution method. Searches for blaTEM, blaSHV, and blaCMY genes in cefotaxime-resistant or intermediate isolates were performed by PCR amplification. PCR products were used to determine the sequence of resistance genes by the dideoxy-chain termination method. RESULTS: Seven percent of E. coli and 25% of K. pneumoniae isolates were resistant to cefotaxime. Among the isolates with decreased susceptibility to cefotaxime, 69% (18/26) of E. coli and 80% (20/25) of K. pneumoniae isolates showed positive results in double disk synergy test. Banding patterns of PCR amplification showed that the blaTEM, blaSHV, and blaCMY genes were harboured by 71% (20/28), 86% (24/28) and 14% (4/28) of isolates with decreased susceptibility to cefotaxime,respectively. Seventy-one percent (20/28) of the isolates contained more than two types of beta- lactamase genes. Nucleotide sequence analysis of PCR products revealed that blaSHV-12 and blaTEM-1b were the dominant types of beta-lactamase gene. In addition, we also identified blaTEM-52, blaSHV-5, and a new ESBL gene named blaTEM-17b. CONCLUSIONS: Third-generation cephalosporins-resistant E. coli and K. pneumoniae are wide spread in Kosin Medical Center, Busan, Korea. Most of the isolates with decreased susceptibility to cefotaxime had blaTEM and/or blaSHV, and some isolates harboured blaCMY genes that may confer resistance against cephamycins. The spread of these beta-lactamase genes could compromise the future usefulness of third-generation cephalosporins for the treatment of infections caused by E. coli and K. pneumoniae.
