ID. of Pathways that can be Targeted for the Develop. of Novel Therapies for MRSA

项目SUMM/VRY(参见说明)： MRSA和VRE菌株利用与哺乳动物感染发病机制有关的特征杀死线虫，该模型系统可用于研究涉及葡萄球菌和肠球菌毒力因子的宿主-病原体相互作用。重要的是，参与哺乳动物致病的金黄色葡萄球菌毒力决定因素，包括群体敏感的全球毒力调节系统AGR、全球毒力调节因子SARA和替代的西格玛因子Sigma(B)是线虫完全致病所必需的。 基于这些观察，我们开发了一种线虫-S。使用384孔板进行的金黄色葡萄球菌筛选试验。这种完整的动物实验可以用来筛选化合物文库，从而能够识别出在传统的体外筛选中无法检测到的防止宿主杀死的化合物。我们的目标是实施这一基于线虫的检测方法，并利用自动化、高通量、全动物筛选来鉴定对MRSA、VRE和VRSA有效的化合物。确定的化合物将通过进行剂量反应和时间过程进行评估 研究，测定体外最低抑菌浓度，确定毒性，并优先在哺乳动物身上测试化合物。我们还建议对以前在线虫-粪便线虫筛查中鉴定的化合物进行表征，并与其他子项目进行协同，以便研究通过线虫检测鉴定的化合物，并表征其他亚对象的化合物。 基于线虫的分析特别吸引人，因为它们允许同时评估毒性和抗微生物活性，以及研究非浮游形式的细菌细胞。因此，虚假线索可以尽早从进一步考虑中消除，新的线索将被清楚地识别出来。除了具有直接抗菌活性的化合物外，基于线虫的检测还将识别影响细菌毒力因子和宿主功能的化合物，提供新的线索，同时也提供新的 探索寄主/病原体相互作用的化学生物学工具。

PROJECT SUMM/VRY (See instructions): MRSA and VRE strains kill C. elegans using traits that contribute to the pathogenesis of infection in mammals, and this model system can be used to study host-pathogen interactions involving staphylococcal and enterococcal virulence factors. Importantly, Staphylococcus aureus virulence determinants involved in mammalian pathogenesis, including the quorum-sensing global virulence regulatory system agr, the global virulence regulator sarA, and the alternative sigma factor sigma(B) are required for full pathogenicity in nematodes. Based on these observations, we developed a C. elegans-S. aureus screening assay that is performed using the 384-well plate format. This whole animal assay can be used to screen compound libraries, allowing the identification of compounds that prevent host killing that would not be detected in traditional in vitro screens. Our objective is to implement this C. elegans-based assay and utilize automated, high-throughput, whole animal screens to identify compounds with efficacy against MRSA, VRE and VRSA. Identified compounds will be evaluated by carrying out dose-response and time-course studies, determining in vitro MICs, determining toxicity, and by prioritizing the compounds for testing in mammals. We also propose to characterize the compounds previously identified in a C. elegans - E. faecalis screen, and synergize with other Subprojects in order to study compounds identified through the C. elegans assays and characterize compounds from other Subrojects. The C. elegans-based assays are particularly appealing in that they allow concurrent evaluation of toxicity and antimicrobial activity, as well as study of bacterial cells that are in a non-planktonic form. Thus false leads can be eliminated from further consideration early, and new leads will be clearly identified. In addition to compounds that have direct antibacterial activity, the C. elegans-based assays will identify compounds that affect bacterial virulence factors and host function, providing new leads, but also new chemical biology tools for exploring host/pathogen interaction.