牛病毒性腹泻病毒、大肠杆菌和奇异变形杆菌混合感染致犊牛腹泻的研究

为确定甘肃省临夏州某奶牛场犊牛腹泻的病因，并提供合适的治疗方案和防控措施，试验采集该牛场13头腹泻犊牛的粪便和血清，通过胶体金技术、ELISA方法、细菌分离鉴定、Kirby-Bauer法分别进行病毒病原学检测、病毒血清学抗体检测、病原菌鉴定和药物敏感性试验。病毒学检测结果显示，13份粪样中未检测出牛轮状病毒（BRV）、牛冠状病毒（BCV）的抗原，牛病毒性腹泻病毒（BVDV）抗原阳性率为23.08%（3/13）；未检出BRV和BCV的抗体，BVDV血清学抗体阳性率为38.46%（5/13）。病原菌检测结果显示，13份粪便样品中，分离出13株大肠杆菌和7株奇异变形杆菌。药敏试验表明，分离的大肠杆菌和奇异变形杆菌对20种常规药物均产生了不同程度的耐药，且无对两种细菌均有效的药物。此次犊牛腹泻是由BVDV、大肠杆菌、奇异变形杆菌混合感染引起的，且大肠杆菌和奇异变形杆菌的耐药现象严重，本试验结果为该牛场进一步治疗此次的犊牛腹泻病提供了合理有效的依据。

Study on Calves Diarrhea Caused by Mixed Infection of Bovine Viral Diarrhea Virus,Escherichia coli and Proteus mirabilis

In order to determine the cause of calves diarrhea and to provide appropriate treatment and prevention measures,13 anal swab samples and 13 serum samples were taken from calves with diarrhea in a scale dairy farm in Linxia of Gansu province. Identification of antibodies to bovine viral diarrhea virus in serum and pathogenic bacteria in diarrhea feces was performed by means of colloidal gold technology, ELISA, bacterial isolation and identification, and Kirby-Bauer method. The virology test results showed that the antigens of bovine rotavirus (BRV) and bovine coronavirus (BCV) were not detected in 13 fecal samples, however the positive rate of bovine viral diarrhea virus (BVDV) was 23.08%(3/13); No antibodies to BRV and BCV were detected in 13 serum samples, whereas the positive rate of BVDV serological antibody was 38.46%(5/13).Pathogen test results showed that 13 strains of Escherichia coli and 7 strains of Proteus mirabilis were isolated from 13 stool samples. Drug sensitivity test showed that isolated Escherichia coli and Proteus mirabilis had different degrees of resistance to 20 conventional drugs; No drug was found to be effective against both of the bacteria at the same time. The calves diarrhea was caused by mixed infection of BVDV, Escherichia coli and Proteus mirabilis. Escherichia coli and Proteus mirabilis were highly resistant to drugs, which provided an effective treatment basis for calves diarrhea in the cattle farm.