新疆昌吉地区猪源喹诺酮耐药大肠杆菌PMQR因子检测及分析

为了解2013年新疆昌吉地区猪源喹诺酮类耐药大肠杆菌携带质粒介导喹诺酮耐药基因的流行情况,采用PCR方法对355株喹诺酮耐药猪源大肠杆菌进行PMQR因子(qnrA、qnrB、qnrC、qnrD、qnrS、qepA、oqxA、oqxB和aac(6′)-Ib-cr)检测,对目的条带进行DNA测序确定基因型。结果显示:该地区猪源喹诺酮耐药大肠杆菌PMQR因子的携带率高达86.8%(308/355),其中42.9%(152/355)的菌株携带2种PMQR因子,11.3%(40/355)的菌株携带3种PMQR因子,6.5%(23/355)的菌株携带4种PMQR因子;检出率较高的PMQR因子有qnrS(62.5%,222/355)、aac(6′)-Ib-cr(55.8%,198/355)、oqxA(26.2%,93/355)和oqxB(29.0%,103/355),未检出qnrA,qnrB,qnrC,qnrD,qepA等基因。与本实验室2010年的调查结果比较,该地区猪源喹诺酮耐药大肠杆菌携带的PMQR因子已从oqxA,oqxB为主发展成以qnrS,aac(6′)-Ib-cr,oqxA,oqxB为主,提示应加强PMQR因子监控。

Detection and analysis of PMQR determinants in Quinolone-resistant Escherichia coli isolates from swine in Xinjiang Changji area

In order to investigate the prevalence and characteristics of plasmid mediated quinolone resistance (PMQR) determinants in quinolone-resistant E.coli from swine in Xinjiang Changji area, polymerase chain reaction (PCR) was used to detect PMQR (qnrA, qnrB, qnrC, qnrD, qnrS, qepA, oqxA, oqxB, aac(6'')-Ib-cr) determinants in 355 strains from swine quinolone-resistant (ciprofloxacin, norfloxacin, enrofloxacin) E.coli.The positive strains were confirmed by using DNA sequencing to determine the objective band.The results showed that qnrS (62.5%, 222/355), aac(6'')-Ib-cr (55.8%, 198/355) oqxA (26.2%, 93/355), oqxB (29.0%, 103/355), were main PMQR determinants in E.coli from swine in Xinjiang Changji area.qnrA, qnrB, qnrC, qnrD and qepA genes were not detected in any of the isolates.86.8% (308/355) quinolone-resistant E.coli from swine in Xinjiang Changji area harbored PMQR determinants, 42.9% (152/355) strains carried two PMQR determinants, 11.3.0% (40/355) strains carried three PMQR determinants, 6.5% (23/355) strains carried four kinds of PMQR determinants.Compared with the result of acquisition in sample survey on 2010, PMQR determinants carried by E.coli from swine, oqxA and oqxB, are replaced by qnrS, aac(6'')-Ib-cr, oqxA and oqxB in this region.Hence, PMQR determinants monitoring should be strengthened in the future.