畜禽及水环境大肠杆菌mcr-1基因的流行病学调查与耐药性分析

Epidemiological Investigation and Drug Resistance Analysis of Escherichia coli mcr-1 in Livestock,Poultry and Water Environment

调查不同来源大肠杆菌mcr-1基因的携带率,大肠杆菌的耐药性和mcr-1基因阳性大肠杆菌的耐药谱,为控制mcr-1流行和多粘菌素的耐药性提供借鉴。采用PCR方法,对实验室前期分离的鸡源、兔源、猪源、屠宰场源、城市污水源、河流和野生鱼源大肠杆菌进行mcr-1基因筛查,并计算携带率,同时检测了8种耐药基因的携带率。对所分离的不同来源大肠杆菌进行氨苄西林、环丙沙星、氟苯尼考、萘啶酸、四环素、头孢他啶、卡那霉素、庆大霉素、阿米卡星、链霉素、阿莫西林、氨曲南和多粘菌素13种常用药物的耐药性分析,计算耐药率、总体耐药率并分析mcr-1阳性大肠杆菌的耐药谱。共采集326份大肠杆菌样本,其中mcr-1阳性大肠杆菌45份,平均携带率为13.8%。鸡源大肠杆菌mcr-1基因携带率为16.3%(16/98),兔源为14.5%(8/55),猪源为8.9%(4/45),屠宰场源为10%(4/40),城市污水源为26%(13/50),河流和野生鱼源均为0。大肠杆菌对抗生素普遍耐药,其中对阿莫西林和氨苄西林的耐药率普遍较高,而对阿米卡星和多粘菌素的耐药率较低。mcr-1携带与多粘菌素的耐药性基本相符,其余药物的总体耐药比例均高于耐药基因的携带率,这可能与同一抗生素的多种耐药机制有关。mcr-1阳性大肠杆菌具有比mcr-1阴性大肠杆菌更高的多药物耐药性。畜禽源大肠杆菌具有较高的mcr-1基因携带率和较广泛的耐药性,应该降低和限制抗生素的使用量,控制耐药基因和耐药性的蔓延。

The purpose of the present study was to investigate the prevalence of mcr-1 gene in Escherichia coli from different sources,drug resistance of E.coli and drug resistance profile of mcr-1 positive E.coli to provide a reference for the control of mcr-1 prevalence and polymyxin resistance.The mcr-1 gene was screened by PCR for E.coli isolated from chickens,rabbits,pigs,slaughterhouses,urban sewage sources,rivers and wild fish.The carrying rates of 8 drug resistance genes was also screened in this study.E.coli strains from different sources were tested for their resistance to ampicillin,ciprofloxacin,fluorine benzene nicol,cefepime,nalidixic acid,tetracycline,ceftazidime,kanamycin,gentamycin,amikacin,streptomycin,amoxicillin,aztreonam and polymyxin to analyze the mcr-1 positive rate.A total of 326 E.coli samples were collected for testing mcr-1 gene,of which 45 were mcr-1 positive with an average carrying rate of 13.8%.The mcr-1 gene carrying rates of E.coli samples were 16.3%(16/98)in chickens,14.5%(8/55)in rabbits,8.9%(4/45)in pigs,10%(4/40)in slaughterhouses,26%(13/50)in urban sewages,and 0 in river and wild fish sources.E.coli was generally resistant to the tested antibiotics,among which the resistance rates to amoxicillin and ampicillin were generally high while the resistance rates to amikacin and polymyxin were relatively low.The carrying capacity of mcr-1 was consistent with polymyxin resistance.In general,the drug resistance ratio of other drugs was higher than the carrying rate of drug resistance genes,which was related to the multiple drug resistance mechanism of the same antibiotic.The mcr-1 positive E.coli had high multi-drug resistance.E.coli from livestock and poultry had high mcr-1 gene carrying rate and extensive drug resistance.Therefore,it is necessary to reduce the use of antibiotics and control the spread of drug resistance gene and drug resistance.