Enzyme Activities and Encoding Genes of Extended-spectrum ?-Lactamases from Clinical Isolates of Gram-negative Bacilli / 中华医院感染学杂志

ABSTRACT

OBJECTIVE To study the molecular mechanism of the drug-resistance of Gram-negative bacilli to the third generation of cephalosporins.METHODS MICs of 13 ?-lactams to the eleven Gram-negative bacilli clinical isolates were detected with the standard agar dilution technique.K-B disc confirmatory method was conducted to determine the ESBLs phenotype of the eleven isolates.The ESBLs encoding genes were analyzed by using PCR.RESULTS The eleven isolates were all resistant to the third generation of cephalosporins(MIC≥64 ?g/ml).Disk confirmatory test showed that 10 isolates produced ESBLs.The hydrolytic activity of the ESBLs from the 10 isolates to cefoperazone and cefamandole was very high.However,the hydrolytic activity of the ESBLs from the 10 isolates to ceftazidime was very low.CONCLUSIONS The enzyme activities and the genes of extended-spectrum ?-lactamases from 10 Gram-negative bacilli clinical isolates are preliminarily analyzed.These results provide the basis for further study on the molecular mechanism of the drug-resistence of Gram-negative bacilli.