Resistant phenotype and genotype of extended spectrum β-lactamase produced in Klebsiella pneumoniae iso1ated from urinary infection in Guangzhou area

Objective:To study the resistant phenotype and genotype of extended spectrum β-lactamase(ESBLs) produced in Klebsiella pneumoniae isolated from urinary infections in Guangzhou.Methods:Organisms of clinical infection were identified by automatic microbial systern(Vitek)and the bacterial susceptibility was tested by Kirby-Bauer(K-B)method as described in NCCLS.ESBLs was detected by disk diffusion confirmatory test and CTX-M(or SHV specific PCR were used to determine the genotype of ESBLs.Results: 41.5% of Klebsiella pneumoniae produced ESBLs.36 of the 54 ESBLs producing strains(66.7%) expressed CTX-M β-lactamase and 29 of the 54 ESBLs producing strains(53.7%) expressed SHVβ-lactamase.The resistant rates of ESBLs-producing isolates against penicillins,ciprofloxacin and the third generation cephalosporins were about 75.9～99.7%.When combined with the lactamase inhibitors,tazobactam and clavulanic acid,the resistant rates were decreased obviously.Conclusion:Klebsiella pneumoniae produced ESBLs is multi-resistance.This study showes that CTX-M-type is predominant genotypes of ESBL in urinary infections in Guangzhou Area.