Resistant Phenotype and Genotype of Extended Spectrum β-lactamase Produced by Klebsiella Pneumoniae Isolated Clinically in Suzhou Area

Objective To study the resistant phenotype and the genotypical characteristics of extended spectrumβ-lactamases(ESBLs) in clinical isolates of Klebsiella pneumoniae.Methods Suzhou 5 hospitals isolated from clinical samples of Klebsiella pneumoniae 512,the provisions of ESBLs were detected from 2006 to 2009,and confirmed by CLSI phenotypic screening and confirmatory tests,the drug susceptibility was tested by the K-B agar diffusion method and TEM,SHV and CTX-M genotypes of ESBLs were determined by the specific PCR method.Results The detection rate of Klebsiella pneumoniae-pro-ducing ESBLs was 35.7%(183),in which 62.8%(115 strain) carrying TEM-type gene,36.1%(66) carrying SHV-type gene,78.7%(144) carrying CTX-M genes.In addition,41.5%(76) also carried two or more genes.For ESBLs-producing strains except for having comparative low resistant rate for the 4th generation of cephalosporin and third generation of cephalosporin with clavulanic acid or tazobactam,resistance rate was,for all other antibiotics have high resistance rate,regardless of ESBLs producing or non producing strains resistance rate for imipenem was 0.Conclusions Klebsiella pneumoniae producing ESBLs in our region has reached a higher proportion and characteristics of multiple drug resistance,inclu- ding CTX-M-type is the main epidemic genotypes.Strictly controlling and rational clinical use of third-generation cephalosporins become essential.