摘要
为确定拉萨市某羊场藏羊发生腹泻、便血、食欲不振、消瘦等症状的病因,采集新鲜血便,进行病原的分离培养,并进行生化鉴定、PCR鉴定和遗传进化分析。结果显示,从藏羊血便、稀粪中分离得到5株细菌,分离株在麦康凯培养基和伊红美蓝培养基上的菌落形态均与大肠杆菌一致,将分离株分别命名为XZ-1、XZ-2、XZ-3、XZ-4、XZ-5;分离菌可以分解葡萄糖、果糖、明胶、甘露醇、麦芽糖、山梨醇、乳糖、尿素酶,硫化氢试验呈阴性;PCR鉴定结果与预期相符,得到大小约为1 500 bp的目的条带;序列分析结果显示,5株分离株之间的同源性为98.7%~100%,与大肠杆菌参考株的同源性为98.5%~100%,分离株与肠炎沙门氏菌的同源性为96.7%~96.9%,与枯草芽孢杆菌分离株的同源性为77.6%~79.1%;分离株16S rRNA基因进化树显示,5株分离株与大肠杆菌处于同一支,而与肠炎沙门氏菌和枯草芽孢杆菌均处于不同分支。研究结果证实,引起藏羊便血、腹泻的病原为大肠杆菌,为该病的防控提供科学依据。
To determine the etiology of diarrhea,blood in stool,loss of appetite and wasting in Tibetan sheep on a sheep farm in Lhasa,fresh blood stool was collected,isolated and cultured for pathogens,and subjected to biochemical identification,PCR identification and genetic evolutionary analysis.The results showed that five strains of bacteria were isolated from blood stool and diluted feces of Tibetan sheep,and the colony morphology of the isolates on McConkey medium and Erythromax blue medium were consistent with E.coli,and the isolates were named XZ-1,XZ-2,XZ-3,XZ-4,XZ-5;the isolates could decompose glucose,fructose,gelatin,mannitol,maltose,sorbitol,lactose,urease,and hydrogen sulfide The PCR identification results were as expected,and the target bands of about 1 500 bp in size were obtained;the sequence analysis results showed that the homology among the five isolates was 98.7%~100%,and the homology with the E.coli reference strain was 98.5%~100%.The homology of the isolates with Salmonella enterica was 96.7%~96.9%,and the homology with Bacillus subtilis isolates was 77.6%~79.1%.The 16S rRNA gene evolutionary tree of the isolates showed that the five isolates were in the same branch with E.coli,while they were in different branches with Salmonella enterica and Bacillus subtilis.The results of the study confirmed that the pathogen causing blood in stool and diarrhea in Tibetan sheep is E.coli,which provides a scientific basis for the prevention and control of the disease.
作者
王冬经
WANG Dongjing(Tibet Livestock Research Institute,Tibet Academy of Agricultural and Animal Husbandry Science,Lhasa Tibet 850009,China;State Key Laboratory of Highland Barley and Yak Germplasm Resources and Genetic Improvement,Lhasa Tibet 850009,China)
出处
《现代畜牧科技》
2023年第8期42-45,共4页
Modern Animal Husbandry Science & Technology
关键词
藏羊
大肠杆菌
分离鉴定
Tibetan sheep
Escherichiacoli
isolation and identification
