携带mcr-1鸡源大肠杆菌耐药性及传播特性的初步分析  

Preliminary study on the drug resistance and transmission characteristics of chicken-derived Escherichia coli carrying mcr-1

作　　者：杨永亚 刘志欢 宋雪艳 谢翠萍 刘洋[1] 邢家宝 陈环环 刘建华[1] YANG Yong-ya;LIU Zhi-huan;SONG Xue-yan;XIE Cui-ping;LIU Yang;XING Jia-bao;CHEN Huan-huan;LIU Jian-hua(College of Veterinary Medicine,Henan Agricultural University,Zhengzhou 450002,China)

机构地区：[1]河南农业大学动物医学院,河南郑州450002

出　　处：《中国预防兽医学报》2021年第7期706-710,733,共6页Chinese Journal of Preventive Veterinary Medicine

基　　金：国家自然科学基金项目(31072170);十三五国家重点研发计划(2016YFD0501304)。

摘　　要：为研究携带mcr-1鸡源大肠杆菌的耐药性、耐药基因的携带情况及mcr-1基因的传播特性,本研究以从河南、湖北、江西等7个省份分离的182株鸡源大肠杆菌作为研究对象,采用PCR方法扩增其mcr-1基因,并对mcr-1阳性菌株携带的其他耐药基因进行检测。结果显示,在182株大肠杆菌中,mcr-1基因阳性率达到18.13%(33/182)。33株mcr-1阳性菌株中,bla TEM、tet A、bla CTX-M-1G基因检出率最高,分别为100%(33/33)、69.7%(23/33)、48.48%(16/33)。tet M及bla OXA-10基因检出率最低,均为3.03%(1/33)。通过接合试验对mcr-1基因的传播进行了研究,并采用脉冲场凝胶电泳技术(PFGE)对接合子进行验证,结果显示,共获得19株接合子。采用微量肉汤稀释法,测定mcr-1阳性菌株及其接合子的最小抑菌浓度(MIC),结果显示,mcr-1阳性菌株对黏菌素全部耐药。MIC在4μg/m L~64μg/m L;多数mcr-1阳性菌株对阿莫西林、头孢噻呋、庆大霉素、恩诺沙星、多西环素、阿米卡星等6种药物呈多重耐药;与受体菌相比,接合子除对黏菌素耐药值升高外,57.89%(11/19)的接合子对庆大霉素耐药,对其他药物无明显变化。以上结果表明,mcr-1阳性鸡源大肠杆菌对黏菌素的耐药情况严重,且存在多重耐药现象。mcr-1基因可在细菌间水平传播,造成大范围的大肠杆菌对黏菌素耐药,氨基糖类耐药基因可能和mcr-1位于相同的可转移元件上。本研究创新性地利用PFGE对mcr-1菌株的疑似接合子进行确证,对mcr-1接合转移机制进行研究,为减缓黏菌素及多重耐药菌株的传播提供实验依据。In order to study the drug resistance and transmission characteristics of chicken-derived Escherichia coli carrying mcr-1,182 chicken-derived Escherichia coli isolates were used as research objects from 7 provinces,including Henan,Hubei and Jiangxi.PCR amplification technology was adopted to detect mcr-1 gene and other drug resistance genes of mcr-1 positive strain.The results showed that the prevalence of mcr-1 gene was 18.13%(33/182).The transmission of mcr-1 gene was studied by conjugation test.Pulse field gel electrophoresis(PFGE) technology was adopted to vertify the conjugation.Among the 33 mcr-1positive strains,the higher detection rates were blaTEM,tet A,blaCTX-M-1G,which account for 100%(33/33),69.7%(23/33) and 48.48%(16/33),respectively.Both tet M and blaOXA-10detection rates were 3.03%(1/33).The transmission of mcr-1 gene was studied through conjugation test,and the transconjugants were confirmed by PFGE.The microbroth dilution method was used to determine the minimal inhibitory concentrations (MICs) of mcr-1 positive strains and their transconjugants.The results showed that 19trans-conjugants were determined.MIC results showed that all of the 33 mcr-1 positive strains were resistant to colistin,with MIC values between 4μg/m L and 64μg/m L.The results of drug sensitivity test and conjugation test showed that most mcr-1 positive strains showed resistance to 6 drugs including amoxicillin,ceftiofur,gentamicin,enrofloxacin,doxycycline,and amikacin.Compared with the recipient E.coli strain C600,except for the increased resistance to colistin,57.89%(11/19) of the transconjugants were resistant to gentamicin,and there was no significant change in resistance to other drugs.The above results indicate that mcr-1 positive chicken-derived Escherichia coli are highly resistant to colistin,and multi-drug resistance occurs.The mcr-1 gene could be spread horizontally among bacteria,resulting in a wide range of Escherichia coli resistant to colistin.In this study,pulsefield gel electrophoresis was innovatively used t

关 键 词：鸡源大肠杆菌 mcr-1 接合试验 药敏试验 脉冲场凝胶电泳 

分 类 号：S852.61[农业科学—基础兽医学]