Interaction between S. aureus and bovine mammary epithelial cells

在乳品工业中，乳腺炎是最昂贵的疾病，其在经济和牛奶生产方面造成显著损失。同样，乳腺炎是动物福利问题，使用抗生素治疗乳腺炎涉及食品和环境安全。虽然许多细菌可引起奶牛乳房炎，但主要原因之一是金黄色葡萄球菌（S。 aureus)具有良好的抗菌活性。S.金黄色葡萄球菌性乳腺炎是传染性的，并且极其难以控制，因为它通常由于S.金黄色葡萄球菌在乳腺上皮细胞中的粘附、侵入和持续存在。S.来自乳房内感染的金黄色葡萄球菌菌株产生许多细胞表面相关产物。大多数产品的确切致病作用及其对粘连和侵袭的影响尚未得到很好的评价。还已知乳腺上皮细胞相关分子与S.金黄色葡萄球菌在乳腺炎发病过程中的作用，但它们在粘附和侵袭中的作用尚未被表征。S.金黄色葡萄球菌和牛乳腺的感染情况非常复杂。本研究的总体目标是利用S.以金黄色葡萄球菌（S. aureus）为模型分子，研究其表面粘附素的作用机制。金黄色葡萄球菌附着并侵入牛乳腺上皮细胞，以及上皮细胞如何对感染作出反应。具体而言，本研究旨在回答以下问题：（1）基因表达在S.金黄色葡萄球菌与牛乳腺上皮细胞相互作用的研究进展(2)不同菌株ClfA重复序列长度的差异对S.金黄色葡萄球菌对乳腺上皮细胞的结合和侵袭有何影响？(3)牛乳腺上皮细胞上的受体是否可以鉴定和分离？本研究结果将为进一步阐明S.金黄色葡萄球菌，从而为更好地预防、治疗和管理奶牛乳房炎提供了新的策略。预计这项研究不会导致任何疫苗的开发。尽管如此，这项研究计划肯定有助于我们对S。金黄色葡萄球菌和牛乳腺。

In the dairy industry, mastitis is the most costly disease that causes significant losses in economic and milk production terms. As well, mastitis is an animal welfare issue and use of antibiotics to treat mastitis is of concern for food and environmental safety. While many bacteria can cause bovine mastitis, one of the major causes is Staphylococcus aureus (S. aureus). S. aureus mastitis is contagious and extremely difficult to control because it usually develops into a chronic infection due to the ability of S. aureus to adhere, invade, and persist in mammary epithelial cells. S. aureus strains from intramammary infection produce many cell surface-associated products. The exact pathogenic roles of most of the products and their effects on adhesion and invasion are not well evaluated. It is also known that mammary epithelial cell-associated molecules interact with S. aureus during the pathogenesis of mastitis, but their roles on adhesion and invasion have not been characterized. The interaction between S. aureus and bovine mammary glands is very complex. The global objective of this proposed research is to use ClfA, a surface protein on S. aureus, as a model molecule to study the mechanisms by which surface adhesins of S. aureus attach to and invade bovine mammary epithelial cells and how epithelial cells respond to the infection. Specifically, this proposed study aims to answer the following questions: (1) How does gene expression change in both S. aureus and bovine mammary epithelial cells during their interactions? (2) How does the varying length of the repeats in ClfA from different strains or isolates of S. aureus affect the binding and invasion to mammary epithelial cells? (3) Is it possible to identify and isolate the receptors on bovine mammary epithelial cells? Results from this proposed study will shed more light on the pathogenic mechanisms of S. aureus and consequently provide new strategies for a better prevention, therapy program and management of bovine mastitis. It is not envisaged that this research will lead to any vaccine development. Nevertheless, this research program will certainly contribute to our basic understanding of the interaction between S. aureus and the bovine mammary gland.