猪源大肠埃希菌喹诺酮类耐药基因的检测及分析  

Detection and analysis of resistance genes in quinolones-resistant Escherichia coli isolated from swine

作　　者：王婧[1] 刁小龙 陈晓兰[1] 王帅兵[1] 杨海峰[1] WANG Jing;DIAO Xiao-long;CHEN Xiao-lan;WANG Shuai-bing;YANG Hai-feng(Jiangsu Agri-animal Husbandry Vocational College,Taizhou 225300,China;Zhongchong Sino Biotech Taizhou Co.Ltd.,Taizhou 225300,China)

机构地区：[1]江苏农牧科技职业学院,江苏泰州225300 [2]中崇信诺生物科技泰州有限公司,江苏泰州225300

出　　处：《甘肃农业大学学报》2020年第2期9-15,共7页Journal of Gansu Agricultural University

基　　金：国家自然科学基金项目(31702286);江苏省高校自然科学基金项目(18KJB230003);江苏农牧科技职业学院科研项目(NSF201704);江苏省高校青蓝工程项目.

摘　　要：【目的】探究江苏泰州地区猪源致病性大肠埃希菌对喹诺酮类药物的耐药情况以及喹诺酮相关耐药因子的流行情况.【方法】采用纸片法对81株临床分离的猪源致病性大肠埃希菌进行喹诺酮类药物耐药性的检测,通过PCR方法检测质粒介导的喹诺酮类耐药基因(PMQR)和喹诺酮类耐药决定区基因(QRDR)并进行分析.【结果】菌株对萘啶酸和环丙沙星的耐药最为严重,耐药率分别为69.1%和51.9%,且多呈现多药耐药现象.PMQR检测结果表明aac(6′)-Ib-cr基因检出率最高,为76.5%,其次为qnrS,qnrA,qnrD,qnrB,检出率依次为45.7%,34.6%,23.6%,2.5%,未检出qepA基因.QRDR突变分析中,常见的gyrA中Ser83突变为Ile, Asp87突变为Asn或Gly和parC中Ser80突变为Ile均被检测到,突变率分别为84.0%,61.7%和60.5%.而gyrB中Asp426突变为Gly还是首次报道,突变率为35.8%.此外,parC还检测到1株Phe64突变为Pro,2株Gln91突变为His.【结论】江苏泰州地区猪源大肠埃希菌中PMQR基因普遍存在,且QRDR基因突变严重,提示应加强抗生素的合理使用以及对喹诺酮相关耐药基因的监控.【Objective】 To investigate the prevalence and characteristics of quinolone-resistant genes in E.coli from pathogens swine.【Method】 Susceptibility of 81 strains to quinolones agents were determined by Kirby-Barer method.Polymerase chain reaction(PCR) was used to detect PMQR and QRDR.【Result】 The pathogenicity isolates showed a high rate of resistance to Nalidixic and Ciprofloxacin and most of them showed multi-drug resistance.The PCR results showed that the aac(6′)-Ib-cr,qnrS,qnrA,qnrD,qnrB were main PMQR determinants,with detected rates of 76.5%,45.7%,34.6%,23.6%,2.5% respectively.The qepA gene was not detected in any of the isolates.Commonly reported point mutations of Ser83 Ile and Asp87 Asn/Gly in gyrA and Ser80 Ile in parC were detected,with mutation rates of 84.0%,61.7% and 60.5%,respectively.Besides,the mutation of Asp426 Gly in gyrB was first reported in E.coli and two novel mutations in parC were found,of which Phe64 Pro occurred in one strain and Gln91 His in another two strains.【Conclusion】 PMQR is prevalent in swine E.coli in Jiangsu and the mutation of QRDR is serious,suggesting that the monitoring of quinolone-related drug resistance genes should be strengthened.

关 键 词：大肠埃希菌 耐药性 PMQR QRDQ 

分 类 号：S852.6[农业科学—基础兽医学]