【摘要】 目的了解南昌大学第二附属医院质粒介导的耐氟喹诺酮类药物大肠埃希菌的流行情况和耐药机制。方法收集该院2009年1月至2011年12月常规培养的耐左氧氟沙星的大肠埃希菌株100株,提取DNA后PCR扩增qnrA、qnrB、qnrC、qnrD、qnrS、aac(6’)-Ib和qepA基因,并对aac(6’)-Ib阳性产物测序比对。结果 (1)7株细菌检测出qnr基因,其中qnrA2株,qnrS 5株,1株qnrS和qnrA同时阳性,qnrB、qnrC和qnrD均未检出。(2)5株检测出aac(6’)-Ib基因,测序结果经BLAST比对均为野生型,未发现aac(6’)-Ib-cr基因。(3)所有菌株均未检测出qepA基因。结论该院的氟喹诺酮类抗菌药的耐药机制主要还是靶位突变和细胞膜通透性改变导致的,但7%的质粒介导的耐药基因的检出率也提醒我们要密切关注质粒介导的耐药情况。更多还原

【Abstract】 Objective To investigate the prevalence and fluoroquinolone resistance mechanisms of E.coli isolates collected in the Second Affiliated Hospital of Nanchang University from January 2009 to December 2011.Methods qnrA,qnrB,qnrC,qnrD,qnrS,aac(6’)-Ib and qepA genes were amplified by PCR from 100 isolates of E.coli.All aac(6’)-Ib PCR products were sequenced to identify aac(6’)-Ib-cr.Results(1) qnr genes were detected in 7 isolates,including qnrA and qnrS in 2 and 5 isolates,respectively.On isolate was detected as carrying both the two genes.None of the isolates carried qnrB,qnrC or qnrD.(2) 5 aac(6’)-Ib positive PCR products were sequenced and none of them were aac(6’)-Ib-cr.(3) qepA was not detected in all isolates.Conclusion The mutation of target and membrane permeability change were considered the main reason of fluoroquinolone resistance of E.coli isolates in the Second Affiliated Hospital of Nanchang University,but the 7% positive rate suggests that we should pay close attention to the plasmid-mediated genes.更多还原