【摘要】 本文对分离自典型大肠杆菌病变和粪便的４５株Ｅ．Ｃｏｌｉ通过４日龄雏鸡人工感染试验建立了大肠杆菌病的人工感染模型，并对菌株的致病性进行评价。结果表明：４日龄雏鸡颈部皮下接种０．２ｍｌ菌液，接种后，前６５ｈ内雏鸡死亡率≥６０％的菌株为强致病力菌株；死亡率＜６０％，或出现典型大肠杆菌病变为中等致病力菌株；试验期不引起雏鸡死亡也无病变者为无致病力大肠杆菌。试验的１３株分离自粪便的苗株，２株为中等致病力，１１株为无致病力；３２株分离自典型病变的菌，９株为强致病力菌，１５株为中等致病力，８株为无致病力。更多还原

【Abstract】 An artificial infection model of colibacillosis in chickens was established in 4-dayold chickens using 45 strains of E.Coli isolated from chickens with typical colibacillosisand feces.Pathogenicity of the strains was also evaluation,The results show that when0.2ml bacteria suspension was inoculated subcutaneously at neck,the strains causingdeath rate of chickens in first 65 hours after infected≥60%in the first 65 hours afterinfection were high-patliogenicity strain.the death rate<60%or typical colibacillosispathologic changes in inoculated chickens were intermediate pathogenic and those causingno death or no pathologic changes during experiment were non-pathogenic.2 strainswere intermediate-pathogenic and 11 strains were non-pathogenic among 13 strainsisolated from feces.In the meantime,9 strains were high-pathogenic,15 strains inter-mediate-pathogenic and 8 strains non-pathogenic among 32 strains isolated from chickens with typical colibacillosis.更多还原