4 株致病性大肠杆菌致犊牛腹泻的分离鉴定及毒力与耐药性分析

[目的]为查明致北疆地区某牧场犊牛腹泻的病原,对脱水濒死10日龄新生犊牛进行剖检,无菌采集充血肠系膜淋巴结2 份。[方法]通过采用培养、染色镜检、生化特性考察、PCR鉴定等方法来分离鉴定致病菌,并对分离致病菌株进行相关毒力基因检测及药物敏感性试验。[结果]经分离鉴定分离出4 株大肠杆菌,毒力基因PCR检测结果K99、Sta、irp2、Eae基因分别在163 bp、314 bp、301 bp、552 bp处有清晰条带,与预期[目的]片段大小相符;药物敏感性试验结果表明,分离株对头孢哌酮、链霉素、庆大霉素敏感,对恩诺沙星、卡那霉素高度敏感。[结论]犊牛腹泻要以预防为主,治疗建议采用对因治疗,并配合提高抵抗力的中兽药进行。

Isolation,Identification,Virulence and Drug Resistance Analysis of Four Strains of Pathogenic Escherichia coli Causing Diarrhea of Calves

[Objective]In order to find out the pathogen causing diarrhea of calves in a pasture in northern Xinjiang,10-day-old dehydrated newborn calves were dissected and 2 mesenteric lymph nodes were collected aseptically. [Method]The pathogenic bacteria were isolated and identified by culture,staining microscopy,biochemical characterization and PCR identification, and the related virulence gene detection and drug sensitivity test were carried out. [Result]Four strains of Escherichia coli were isolated and identified. The results of virulence gene PCR showed that K99,Sta,irp2 and Eae genes had clear bands at 163 bp,314 bp,301 bp and 552 bp,respectively,which were consistent with the expected target fragment size. The results of drug sensitivity test showed that the isolates were sensitive to cefoperazone,streptomycin and gentamicin,and the isolates were highly sensitive to enrofloxacin and kanamycin.[Conclusion]Calf diarrhea should be based on prevention. It is recommended to use Chinese veterinary drugs to improve resistance due to treatment.