犊牛大肠杆菌病病原的分离鉴定

Isolation and Identification of Diarrhea Pathogen Caused by Pathogenic Escherichia coli in Calves

从陕西杨凌某发病牛场采取腹泻犊牛病料5份,经微生物学诊断,从中分离出革兰阴性疑似致病菌6株。经生物学特性和生理生化试验鉴定,6株分离菌均为致病性大肠埃希菌。对分离菌进行抗生素敏感性试验,结果表明,该致病菌对氯霉素、菌必治、氧氟沙星、阿米卡星及卡那霉素等高度敏感;对妥布霉素、呋喃妥因和复达欣等中度敏感,对链霉素、庆大霉素、利福平、复方新诺明、四环素及红霉素等有较强的耐药性。动物致病性试验结果表明,该菌对小鼠有强致病性。

5 samples selected from the of diarrhea calves in Yangling of Shaanxi province were diagnosed by the microbiological methods, and 6 strains of Gram-negative bacteria were isolated from the feces samples. According to the biological characteristics, physiological and biochemical tests, all of the 6 isolated strains were identified as pathogenic Escherichia coli. Antibiotic sensitivity tests showed that the 6 isolated strains were highly sensitive to some antibiotics such as chloramphenicol, ceftriaxone sodium, ofloxacin, amikacin and kanamycin, moderately sensitive to nitrofurantoinum, tobramycin and fortum, but not sensitive to streptomycin, gentamicin, rifampicin, compound sulfamethoxazole, erythromycin and tettacycline. The pathogenic test showed that the 6 isolated strains were strong pathogenic to mice.