一起奶牛大肠杆菌病的诊断

Diagnosis of Cow Colibacillosis

2011年,宁夏某奶牛场成年牛陆续出现以排酱油色稀水样或血样粪便,其中有大量气泡且恶臭、眼底出血、呼吸困难、食欲减退、体温升高和关节炎为主要特征的病例,截止送检已死亡9头。根据临床症状、病例剖检,疑似为大肠杆菌病。经对病料病原体分离培养、生化鉴定、PCR检测及毒力基因序列比对及药敏试验,结果表明,该病为牛致病性大肠埃希菌O157:H7感染引起;此菌株耐药情况严重,对头孢类药物极敏,对庆大霉素、阿米卡星高敏,对红霉素、环丙沙星、苯唑西林、青霉素都不敏感。

In 2011 ,adult cow were sick continuously and nine cows died in a dairy cow farm in Ningxia. The affected cattle lost appetite, discharged dark reddish brown watery or bloody malodorous feces contained a lot of bubbles. Body temperatures were increased and breath became difficult. Haemorrhage on the eye ground and arthrocele could be found. After dissecting the died cows, some specimen were used to isolate pathogenic bacteria. The pathogenic bacteria were identified by biochemical and molecular biology experi- ment. The virulence genes were amplified and aligned. The drug sensitivity tests were conducted to assess the resistance of the pathogenic bacteria. The results showed that Escherichia coil O157：H7 caused the disease. The isolate is highly sensitive to cephalosporin, relatively sensitive to gentamicin and amikacin, not sensitive to erythromycin, ciprofloxacin, oxacillin and penicillin.