金黄色葡萄球菌小菌落突变株侵袭奶牛乳腺上皮细胞的机制研究

金黄色葡萄球菌小菌落突变株(SCVs)感染奶牛引起慢性乳房炎，造成巨大的经济损失。通过检索可知，加拿大和阿根廷已发表金黄色葡萄球菌SCVs致奶牛乳房炎的文章，但其机制还不清楚。国内尚未见金黄色葡萄球菌SCVs致奶牛乳房炎的报道。本课题旨在通过慢性乳房炎病牛乳汁分离鉴定牛源金黄色葡萄球菌SCVs，研究SCVs的生理生化特性和表观遗传学特点，检测SCVs的突变基因，筛选SCVs的毒力基因和开展SCVs毒力基因的蛋白组学研究，建立SCVs体外感染乳腺上皮细胞和体内感染动物的模型，分析金黄色葡萄球菌 SCVs体内外感染时的持续状况及各种病理变化等，揭示金黄色葡萄球菌SCVs侵入奶牛乳腺上皮细胞的机制，为奶牛慢性乳房炎的防治提供重要的理论依据。

Staphylococcus aureus small colony variants （SCVs）are a frequent cause of mastitis in dairy cows. However, pathogenesis of the infection has not been completely defined. The objective of this study is to 1) isolate bovine original S. aureus SCVs from bovine milk of chronical mastitis, 2) study the physiological, biochemical and epigenetic characters of S. aureus SCVs, 3) detect the mutant genes, 4) select the virulent genes and analyze the proteomics of SCVs, 5) demonstrate the invasion of the strain of S. aureus SCVs into a bovine mammary epithelial cell line and a bovine mammary epithelial cell primary culture, 6) analyze in vitro infection persistence, host immune protection and pathological changes,so as to indicate that S. aureus SCVs is capable of invading and replicating in bovine mammary epithelial cells. Data also suggested that S. aureus SCVs invasion of bovine mammary epithelial cells requires active participation of specific components of the cytoskeleton of the epithelial cell. the program will provide important theory bases to the prevention of chronical bovine mastitis.