1株乳房链球菌的分离鉴定及生物学特性研究

Isolation,identification and biological characteristics of a strain of Streptococcus uberis

试验旨在分离并研究乳房链球菌的特性。试验从南京某奶牛养殖场中分离到1株乳房链球菌,对其进行鉴定并进一步研究其生化特征、生长曲线、抗生素敏感性、培养条件优化等。结果显示,该株乳房链球菌与七叶苷等反应阳性,与棉籽糖等反应阴性;该菌在37℃、200 r/min条件下培养16~20 h达到最高菌数水平;适当增加培养基中蛋白胨的含量可提高该菌的菌数水平。药敏试验结果显示,该菌对青霉素、羧苄西林、头孢唑林等抗生素高度敏感。研究表明,试验分离的乳房链球菌可作为乳房炎疫苗的筛选株。

The test was designed to isolate and study the properties of Streptococcus uberis.In the experiment,a strain of Streptococcus uberis was isolated from a dairy farm in Nanjing,and its biochemical characteristics,growth curve,antibiotic sensitivity,and optimization of culture conditions were further studied.The results showed that the strain of Streptococcus uberis had positive reactions with esculin,and negative reactions with raffinose.The strain reached the highest bacterial count when cultured at 37 ℃ and 200 r/min for 16~20 h.Appropriately increasing the content of peptone in the medium can increase the bacterial count level of the bacteria.The drug susceptibility test results showed that the bacteria were highly sensitive to antibiotics such as penicillin,carbenicillin and cefazolin.The study indicates that the Streptococcus lactis isolated in the test can be used as a screening strain for mastitis vaccine.