奶牛乳房炎金黄色葡萄球菌毒力因子检测与基因分型

Investigation on Virulence Determinants and Genetic Typing of Staphylococcus aureus Isolated from Mastitis Milk

用PCR方法对新疆乌鲁木齐周边3个奶牛场奶牛乳汁中分离到的49株金黄色葡萄球菌的entA、tsst-1、nuc、clfA、fnbA、fnbB、hla、hlb8种毒力基因进行分子流行病学调查，并用肠道细菌基因间重复序列-PCR（ERIC—PCR）法对这49株金黄色葡萄球菌进行基因分型。结果：tsst-1、nuc、clfA、fnbA、fnbB、hla、hlb、entA毒力基因的检出率分别为4％、59．2％、63．3％、69．4％、22．5％、46．9％、53．1％、0，且以cZfA、fnbA为主要检出毒力基因。ERIC—PCR分型结果显示：49株金黄色葡萄球菌可扩增出3～7条带，共分为4个聚类群，在同一牛场中的分离株存在不同基因型；而不同牛场中的分离株也可属于同一基因型。这种结果提示，在不同环境下同一种病原菌的基因型存在一定差异，可能存在多个金黄色葡萄球菌的流行株。

Molecular investigations on the genes encoding virulence determinants entA, tsst-1, nuc, clfA,fnbA,fnbB, hla, hlb were conducted within 49 strains of Staphylococcus aureus isolated from subclinical mastitis by means of PCR and typed by Enterobacterial Repetitive Intergenic Consens-PCR （ERIC-PCR）. The results I：evealed that the positive rate of tsst-1 ,nuc,clfA,fnbA,fnbB,hla,hlb,entA were4%,59.2%,63.3%,69.4%,22.5%,46.9%,53. 1%,0. ClfA and fnbA are predominant virulence determinants. ERIC-PCR could be amplified out 3- 7 straps, revealeing 4 genotype. Isolates from the same cow farm belonged to the different gene type, and isolates from different farms belonged to the same gene type. This suggested that the different genotypes of pathogenic bacteria can exist in different environments.