奶牛乳房炎金黄色葡萄球菌的分离鉴定及毒力基因检测

Identification and investigation on virulence determinants of Staphylococcus aureus isolated from bovine mastitis

为研究奶牛乳房炎金黄色葡萄球菌毒力基因的分布情况,本试验通过MALDI Biotyper系统对分离自3个奶牛场的25株金黄色葡萄球菌进行鉴定及聚类分析,并采用PCR方法对25株金黄色葡萄球菌的nuc、clfA、fnbA、fn-bB、tsst-1、sea、seb和sec等14种毒力基因进行检测。结果显示,25株金黄色葡萄球菌被分为3个类群,各个类群之间及类群内菌株遗传距离较远。14种毒力基因中有7种被检出,检出率分别是nuc(100%)、fnbA (100%)、seg(64%)、clfA(52%)、fnbB(32%)、tsst-1(16%)和sea(4%),其余未检出。结果表明,不同奶牛场甚至同一奶牛场内存在多种金黄色葡萄球菌的流行株,且金黄色葡萄球菌携带毒力基因的数量和种类不同,并存在多种毒力基因组合,为奶牛金黄色葡萄球菌性乳房炎的防治提供基础研究。

The aim of this study was to determine the virulence genes of S.aureus isolates from bovine mastitis in three dairy farms.Twenty-five S.aureus isolates were confirmed and typed by MALDI Biotyper system.Fourteen virulence genes were investigated by PCR,including nuc,clfA,fnbA,fnbB,tsst-1,sea,seb and sec,etc.The results showed that 25 S.aureus isolates were divided into 3groups,and the genetic distance between the groups and the strains within the group was far away.In the 25 S.aureus isolates,the most prevalent virulence genes were nuc(100%)and fnbA(100%),followed by seg(64%),clfA(52%),fnbB(32%),tsst-1(16%)and sea(4%),and other virulence genes were negative.So there are different S.aureus prevalence in the same or different dairy cow farms.In the meanwhile,the number and type of virulence genes in S.aureus isolates are different,and there are also several combinations among them,which provide the fundamental researches for the prevention and treatment of bovine S.aureus mastitis in clinic.