猪源大肠埃希菌中质粒介导喹诺酮耐药(PMQR)基因的多样性研究  

Diversity of Plasmid-mediated Quinolone Resistance(PMQR)Genes in Escherichia coli form Swine

作　　者：郭晶晶 侯思梦 刘连杰 邱芳 刘晓强[1] GUO Jingjing;HOU Simeng;LIU Lianjie;QIU Fang;LIU Xiaoqiang(College of Veterinary Medicine, Northwest A&F University, Yangling Shaanxi 712100, China)

机构地区：[1]西北农林科技大学动物医学院,陕西杨凌712100

出　　处：《西北农业学报》2021年第11期1611-1617,共7页Acta Agriculturae Boreali-occidentalis Sinica

基　　金：陕西省重点研发计划(2018NY-005)。

摘　　要：为研究陕西省关中猪源大肠埃希菌的耐药情况及质粒介导的喹诺酮耐药(PMQR)基因的流行性与多样性,于2017年4月—2018年11月从陕西关中地区数个养猪场分离获得470株大肠埃希菌,采用微量肉汤稀释法测定其对包括3种氟喹诺酮类药物在内的6类抗菌药物的最小抑菌浓度(MIC),PCR扩增检测其携带的PMQR基因,并分析PMQR基因阳性菌株gyrA和parC基因的质粒介导喹诺酮耐药决定区(QRDR)的突变情况。结果显示,陕西猪源大肠埃希菌对阿莫西林和土霉素的耐药率高达100%和98.51%,对阿米卡星、氟苯尼考、替米考星和头孢噻呋的耐药率分别为60.64%、52.98%、50.85%和44.47%,且89.58%为多重耐药菌株。对3种氟喹诺酮类药物恩诺沙星、普多沙星和环丙沙星的耐药率分别为89.58%、57.66%和56.80%。对美罗培南最为敏感,未发现耐药菌株,但有9株大肠埃希菌对美罗培南的敏感性为中介。对氟喹诺酮类药物耐药的菌株中,PMQR基因qnrS、aac(6′)-Ib-cr、qnrB、qnrA、qnrD和qepA的检出率分别为36.52%、30.14%、17.38%、11.45%和2.49%,且55.30%的菌株携带1种PMQR基因,37.90%携带2种PMQR基因,6.40%携带3种PMQR基因,0.35%携带4种PMQR基因。在282株携带PMQR基因的菌株中,279株发生QRDR突变,其中以gyrA基因的Ser83Leu突变为主。132株PMQR基因阳性菌株parC基因发生Ser80Ile或Ser80Ile+Glu84Val突变。随着菌株所携带PMQR基因的增多,gyrA和parC基因的突变位点也相应增加,细菌的耐药水平也随之增加。The aim of this study is to investigate the antimicrobial resistance,prevalence and diversity of plasmid mediated quinolone resistance(PMQRs)genes among the Escherichia coli from pigs in Guanzhong area of Shaanxi province.A total of 470 E.coli isolates were isolated from several pig farms in Guanzhong area from April 2017 to November 2018.The minimal inhibitory concentrations(MICs)of six kinds of antimicrobial agents which included three fluoroguinolones were determined by microdilution broth method.PCR amplification was used to detect the PMQR genes among the fluoroquinolone resistant isolates based on the susceptibility test.The mutations in the quinolone resistance-determining region(QRDR)of gyrA and parC were investigated in the PMQR positive isolates by PCR and sequencing.The results showed that the tested isolates had high degree of resistance to amoxicillin(100%)and oxytetracyclin(98.51%),and the resistant rates of amikacin,florfenicol,tilmicosin and ceftiofur were 60.64%,52.98%,50.85%and 44.47%,respectively.89.58%of tested isolates were classified as multidrug-resistant(MDR)isolates.Furthermore,the resistant rates of three fluoroquinolones,including enrofloxacin,pradofloxacin and ciprofloxacin,were 89.58%,57.66%and 56.80%,respectively.No isolate was found to be resistant to meropenem,nine isolates showed intermediate susceptibility to meropenem.Among the fluoroquinolones-resistant isolates,the six tested PMQR genes were detected,and the prevalence of the PMQR genes qnrS,aac(6′)-Ib-cr,qnrB,qnrA,qnrD and qepA were 36.52%,30.14%,17.38%,11.45%and 2.49%,respectively.55.30%,37.90%and 6.40%of the fluoroquinolone-resistant isolates carried one,two and three PMQR genes,respectively,and one(0.35%)isolate carried four PMQR genes.QRDR mutations were detected in 279 of the 282 PMQR positive E.coli isolates,and the single mutation Ser83Leu in gyrA gene appeared in most of the isolates.The single mutation Ser80Ile or double mutations Ser80Ile+Glu84Val in parC gene were detected in 132 isolates.Additionally,the QRDR mu

关 键 词：氟喹诺酮类药物 大肠埃希菌 耐药性 PMQR基因 QRDR突变 

分 类 号：S859.7[农业科学—临床兽医学]