Resistant Genes Associated with Extended-spectrum ?-Lactamases in Escherichia coli / 中华医院感染学杂志

ABSTRACT

OBJECTIVE To investigate resistance to antimicrobials and resistant genes associated with ?-lactamases in Escherichia coli isolated from Changzhou district. METHODS Minimum inhibitory concentrations (MIC) of ampicillin,piperacillin,piperacillin/tazobactam,cefotaxime,ceftazidime,cefepime,aztreonam and imipenem were determined by agar dilution. Seventeen resistant genes of E. coli encoding ?-lactamases including TEM and SHV were detected by PCR amplification and sequenced by DNA sequencer. RESULTS The detecting rates of extended-spectrum ?-lactamases in 80 Klebsiella pneumoniae isolates was 46.3%(37/80). Five ?-lactamase resistant genes including TEM,SHV,CTX-M-1group,OXA-1group and DHA in 37 isolates were found,and their rates were 81.1%,78.4%,21.6%,10.8% and 5.4%,respectively. Of 37 strains,at least one ?-lactamase gene was detected in 36 strains. More than two ?-lactamase resistant genes were simultaneously isolated from 24 strains.Furthermore,four ?-lactamase resistant genes were found in one strain.Only one strain wasn't detected out ?-lactamase gene. CONCLUSIONS E. coli has carried various kinds of ?-lactamase resistant genes in Changzhou district,which become the important causes of resistance to ?-lactam antimicrobials.