中文摘要：

为探讨细菌对消毒剂和抗菌药物耐药性之间的相关性,本试验分别用亚抑菌浓度苯扎溴铵和土霉素分别对大肠埃希菌质控菌ATCC25922进行体外诱导,测定诱导前后最小抑菌浓度（MIC）的变化;并对诱导后菌株外排泵调控基因acr R、mar A、sox S、rob进行PCR扩增和测序,检测其突变情况。结果显示,菌株经苯扎溴铵和土霉素诱导后对苯扎溴铵和土霉素均产生了耐药性,且诱导后的菌株有相同基因的同一位点发生突变,mar A、sox S所编码的氨基酸也有同一位点发生突变,提示大肠埃希菌对苯扎溴铵及土霉素的交叉耐药与调控基因位点的突变有一定相关性。

英文摘要：

To explore the correlation of resistance between disinfectants and antimicrobial drugs,Escherichia coli control strainwas separately induced in vitro by sub-inhibitory concentration of benzalkonium bromide and oxytetracycline,and the change ofMIC before and after induction was determined.The mutations of acr R,mar A,sox S and rob that are regulator genes of Acr AB-Tol Cefflux pump were determined by PCR amplification and sequencing. The results showed that the induced strains produced resis-tance against both benzalkonium bromide and oxytetracycline.And there were mutations occurred at the same site on the same geneof the two induced strains.The change of amino acid sequence that encoded by mar A and sox S was nearly the same.These resultssuggest that one multi-drug resistant reason of the two induced strains is probably the mutations of the Acr AB-Tol C efflux pumpregulator genes.