Isolation and Identification of a Strain of Corynebacterium xerosis from Beef Cattle
To determine the cause of the disease in beef cattle on a beef farm in Changli County,Hebei Province,a dominant strain was isolated and purified from the nasal mucus of diseased cattle with obvious respiratory symptoms,and identified by bacterial culture,Gram staining,bacterial biochemical identifica-tion,rpoB gene detection and 16S rRNA sequence analysis.The drug susceptibility of the isolate to 18 an-tibiotics such as tylosin and cefradine was tested by K-B test paper.The test results showed that the isolate was positive for Gram staining of short rod-shaped cocci,and could grow as dry and rough yellowish colo-nies on blood agar medium,and precipitated in LB liquid medium,with slight turbidity in the upper layer and granular and flaky precipitation in the lower layer.The isolate was identified as having lipase,lysine decarboxylase,β-glucosidase and a-glucosidase activities,and was able to ferment algose,maltose and su-crose,which were consistent with the biochemical characteristics of Corynebacterium xerosis.The homolo-gy and consistency of 16S rRNA sequences with Corynebacterium saudium were 99％and 91.6％.It was resistant to seven drugs,such as Tylomycin and cefradine,and sensitive to nine drugs,such as ciprofloxa-cin and Ennoxacin.The test results show that the isolate is Corynebacterium xerosis.
beef cattleCorynebacterium xerosisbiochemical identificationrpoB gene16S rRNAdrug sensitivity test
万方数据
维普
