2018年湖北省猪源沙门菌的分离鉴定及耐药性分析

Isolation and antimicrobial resistance of porcine Salmonella isolates from Hubei Province in 2018

为了解规模化猪场沙门菌的流行和耐药情况,本研究于2018年10-12月采集湖北武汉、钟祥、大冶、襄阳、黄冈地区5个规模化猪场各年龄段猪的肛门拭子进行沙门菌的分离鉴定,并对所分离的菌株进行耐药表型分析和耐药基因检测。采用沙门菌选择性培养基进行细菌的分离培养,并通过生化试验和PCR扩增invA基因确定所分离的细菌为沙门菌;采用玻片凝集法对所分离的沙门菌进行血清分型;采用微量肉汤稀释法进行6种抗菌药物的耐药表型检测,并采用PCR方法对相关的15种耐药基因的携带情况进行检测。结果显示,从采集的640份肛门拭子分离鉴定出39株沙门菌,分离率为6.09%,其中来源于保育猪的样品中沙门菌的分离率最高,为16.25%;所分离沙门菌的血清型主要为鼠伤寒沙门菌(69.23%),其次是德比沙门菌(15.38%),其他血清型所占比例为15.38%。药敏试验发现所分离的沙门菌至少对1种抗生素耐药,其中94.87%的分离株对氨苄西林表现出耐药性,对氯霉素和卡那霉素表现出耐药性的分离株所占的比例分别为58.97%和53.84%,仅有20.51%的分离株对阿奇霉素表现出耐药性;此外,53.84%的菌株对3种以上的受试抗生素同时表现出抗性,其中20.51%的分离株同时对5种受试抗生素表现出耐药性。用PCR方法共检测出12种耐药基因,其中blaCMY(79.49%)、aph(3′)-Ⅱ(76.92%)、catA1(76.92%)的检出率较高。研究结果为湖北地区猪场制定沙门菌病的综合防控措施提供参考。

To understand the prevalence and antimicrobial resistance profile of Salmonella in industrial pig farms in Hubei Province.In this study,anal swabs of pigs at different ages from five industrial farms in Wuhan,Zhongxiang,Daye,Fuyang and Huanggang in Hubei Province between October 1 and December 31,2018 were collected for Salmonella isolation and identification.Resistant phenotypes of the Salmonella isolated herein as well as the presence of selected resistance genes were also determined.Salmonella isolates were recovered through bacterial culture on Salmonella selective media,followed by biochemical tests and PCR detection of the invA gene.Serotypes of the Salmonella isolated herein were determined by slide agglutination.Phenotypes on the six types of antibiotics tested were determined using broth microdilution method.The presence of 15 kinds of resistance genes were detected by PCR.The results showed that a total of 39 Salmonella strains were finally isolated from the 640 samples collected,with an isolation rate of 6.09%.Samples from weaned pigs processed the highest isolation rate of Salmonella,which was 16.25%.The main serotypes of the Salmonellastrains isolated herein were Salmonella typhimurium(69.23%),followed by Salmonella derbyx(15.38%),and the other serotypes(15.38%).Antimicrobial suscepitibility testing showed that all of the Salmonellaisolated herein were resistant to at least one type of antibiotics tested.Approximately 94.87%of the isolates were resistant to ampicillin,while 58.97%and53.84%of the isolates were resistant to chloramphenicol and kanamycin,respectively.Only 20.51%of the isolates were resistant to azithromycin.Approximately 53.84%of the isolates showed resistance to more than three types of antibiotics tested,simultaneously.Among which 20.51%of the isolates were resistant to 5 types of the antibiotics tested,simultaneously.A total of 12 kinds of antimicrobial resistance genes were detected by PCR.Of which,blaCMY(79.49%),aph(3′)-Ⅱ(76.92%),and catA1(76.92%)processed a high rate of detection.The results from the present study provide a reference for the comprehensive prevention and control of Salmonellosis in pig farms in Hubei Province.