Detection of drug resistance and genotype of extended-spectrum β-lactamases producing Escherichia coli

Objective To explore the molecular epidemiology and antimicrobial resistance of extended-spectrum β-lactamases (ESBLs) producing Escherichia coli. Methods The strains of ESBLs-producing Escherichia coli were identified by disk diffusion method and confirmatory test. The ESBLs encoding genes were amplified by PCR. The antibiotic susceptibility of clinical isolates were tested by Kirby-Bauer method. Results In 124 clinical isolates of Escherichia coli analyzed,54 ESBLs-producing isolates were detected (43.5%). The resistance rates of Escherichia coli to piperacillin/tazobactam,cefoperazone/sulbactam,imipenem were 3.7%,0.0% and 5.6% respectively. In 54 ESBLs-producing strains,TEM-type,SHV-type,CTX-M-type ,OXA-type accounted for 23,13,41,8 respectively,and ESBLs encoding gene mainly belonged to CTX-M-type. Conclusion The fact that the occurrence of ESBLs-producing Escherichia coli increased significantly in the region should be paid more attention to. The major ESBLs encoding gene is CTX-M-type,and some strains carrying two or more than two types of drug resistance genes. Piperacillin/tazobactam,cefoperazone/sulbactam,imipenem are suitable in managing the infection caused by ESBLs-producing Escherichia coli strains.