6株牛源副乳房链球菌的分离和鉴定

Isolation and identification of six Streptococcus parauberis from cow

从奶牛临床型乳房炎乳汁中分离出6株细菌，通过生化试验、16srDNA鉴定、小鼠致病性和抗生素耐药性检测，结果显示，这6株细菌为革兰阳性链球菌，与副乳房链球菌（Spu）同源性为990；在血琼脂平面上产生α溶血，过氧化氢酶反应阴性，CAMP试验阴性；对小鼠有不同程度的致病性，半数致死量（LD50）为5．6×10^7-5．2×10^-8CFU；对四环素耐药，对氨苄西林、氯霉素、红霉素、卡那霉素、氧氟沙星和万古霉素敏感。本试验检出并报道牛源Spu，研究数据将有助于进一步开展Spu与奶牛乳房炎之间的相关性研究。

Six bacteria were isolated from milk of cow with clinical mastitis,and biochemical tests, 16S rDNA identification,mouse pathogenicity and antibiotic resistance were carried out. The result showed the 6 isolates gram positive Streptococcus shared 99% homology with Streptococcus parauberis ,which had biochemical reaction of a-hemolysis, catalase-negative, and CAMP-negative, displayed varying degrees of pathogenicity to mice with LD50 of 5. 6× 10^7- 5.2× 10^8 CFU, were resistance to tetracycline but sensitive to ampicillin, chloramphenicol, erythromycin, kanamycin, ofloxacin and vancomycin. It was the first time to detect S. parauberis from cow in domestic,and the data contribute to further understand the correlation between S. parauberis and cow mastitis.