奶牛产气荚膜梭菌的分离鉴定与药物敏感性分析

本研究旨在对从奶牛内脏、组织病料样品中分离得到产气荚膜梭菌并进行鉴定分型，为后续疫苗研究提供材料，并通过药敏试验筛选出较为敏感的药物以针对性的指导牧场对牛群进行治疗并提出有效的防治隔离建议。2019年山东21家牧场部分奶牛出现腹泻、便血及短期内死亡等现象，对部分死亡奶牛进行剖检，并送检64份内脏、组织病料样品进行CP培养初筛，对初筛阳性菌株用生化鉴定及PCR分型鉴定；以16S rDNA技术对CP菌株进行同源性分析；采用E-test法测定分离菌对7种抗菌药物（红霉素、左氟沙星、利奈唑胺、万古霉素、克林霉素、四环素、利福平）的最低抑菌浓度（micro inhibition concentration，MIC），筛选出敏感药物。8份样品血琼脂培养基细菌培养出现灰白色菌落，梭菌显色培养基培养为橘红色梭菌典型特征菌落；生化鉴定结果符合产气荚膜梭菌特征；PCR分型结果显示5株为A型、2株C型和1株E型；16S rDNA分析得出8株分离菌与产气荚膜梭菌同源性最高可达100%；8株CP菌株对7种药物敏感，其中2株对克林霉素、利福平更为敏感，3株对红霉素及利奈唑胺敏感，1株对左氟沙星更敏感。对有病牛的2家牧场推荐使用林可酰胺类、利福霉素类及大环内酯类药物进行防治，对牧场防治效果及时追踪，对于没有治疗价值的牛立即扑杀，无害化处理，改善饲养条件，减小饲养密度。

Isolation and Identification of Clostridium perfringens from Dairy Cows and Analysis of Drug Sensitivity

The purpose of this study was to isolate and classify Clostridium perfringens (CP) strains from cow viscera and tissue samples to provide materials for subsequent vaccine studies,in addition,sensitive drugs were screened out through drug sensitivity test to guide the pasture to treat cattle and effectively control and isolate cattle without disease.In 2019,some cows in 21 ranches in Shandong province reported diarrhea,hematochezia and short-term death.Some of the dead cows were dissected,and 64 viscera and tissue samples were sent to be cultured for CP preliminary screening,then the positive strains was identified by biochemical identification and PCR typing.The homology of strains was analyzed by 16S rDNA technique.The minimal bacteriostatic concentration of isolated strains against 7 kinds of antibiotics (erythromycin,levfloxacin,linezolid,vancomycin,clindamycin,tetracycline,rifampicin) was determined by E-test method,and sensitive drugs were screened out.8 samples showed gray,orange and black colonies on blood medium,CP chromogenic medium and TSC medium respectively.The biochemical identification results were consistent with the characteristics of CP.PCR typing results showed that 5 A-type strains,2 C-type strains,1 E-type strain.The homology of 8 isolates and Clostridium percapsulatum was up to 100% by 16S rDNA analysis;Among the 8 strains,2 were more sensitive to clindamycin and rifampicin,3 more sensitive to erythromycin and linezolid,1 more sensitive to levfloxacin.Lincoamides,rifamycin and macrolide were recommended for the prevention and control of two farms with diseased cattle.The effect of the prevention and control on the farms was tracked in time.The cattle without therapeutic value were immediately culled and treated innocuously,so as to improve the feeding conditions and reduce the feeding density.