中文摘要：

目的自1998年报道质粒介导的喹诺酮类药物耐药基因(PMQR)qnrA以来,qnrB、qnrC、qnrD、qnrS、oqxAB、qepA和aac(6’)-Ib-cr等质粒介导的耐药基因被陆续报道,本文对中国分离的猪源大肠杆菌进行质粒介导的喹诺酮类药物耐药基因分析。方法在1998—2007年间从中国分离到的198株猪源大肠杆菌中,运用PCR、接合试验、药物敏感性试验、S1-PFGE和Southern blot等方法对其进行研究。结果和结论 2004年从辽宁省分离到的一株猪源大肠杆菌中含有qnrA1和aac(6’)-Ib-cr基因,另有2005年从江苏省同一猪场分离到的三株细菌中含有qnrA3和aac(6’)-Ib-cr基因。通过S1-PFGE和Southern blot证实qnrA和aac(6’)-Ib-cr位于同一质粒上,其共同转移可使环丙沙星MIC值升高32~128倍,并且接合子表现对氨苄西林的耐药性。

英文摘要：

The prevalence of plasmid-mediated quinolone resistance （PMQR） determinants was determined in 198 E. coli isolates, which separated from pigs during 1998-2007 from China. Four isolates were found to be positive for qnrA gene. One isolate from Liaoning Province in 2004 was positive for qnrA1 ＋aac（6＇）-Ib-cr and the other three isolates, which derived on the same pig farm in 2005 in Jiangsu Province, were positive for qnrA3＋aac（6＇）-Ib-cr. The qnrA and aac（6＇）-Ib-cr genes were located on the same plasmid. The cotransfer of the two genes led to the minimum inhibitory concentration （MIC） to ciprofloxacin increasing 32- to 128- fold. The qnrA1 and qnrA3 in combination with aac（6＇）-Ib-cr in E. coli strains from pigs in China were reported.