Antimicrobials and Efflux Pumps in Staphylococcus aureus Infection

项目总结(见说明)： 该项目的长期目标是确定导致多重抗菌素耐药的金黄色葡萄球菌外排泵的完整阵列，并阐明它们表达的决定因素、它们在微生物生理学中的作用以及它们对感染中细菌对抗菌素反应的影响。这项工作将侧重于皮下脓肿模型中调节元件的遗传分析以及细菌适合性和抗菌剂的反应，并与其他项目组合作，评估新型抗菌剂化合物在脓肿中的疗效以及外排泵对该疗效的影响程度。有四个具体目标：1)在感染的动物模型中评估Norb、Nord和Tet38外排泵及其调节因子对抗菌药反应的影响；2)评估编码ABC家族外排泵的ABCA的表达调控，并评估其对膜和细胞壁靶向制剂的影响；3)分析在脓肿环境中过度表达的泵的全球阵列，并确定它们对已有制剂和新化合物的耐药性的贡献；以及4)测试在该计划的其他子项目中发现的新化合物对外排泵的表达的耐药性，以及在哺乳动物感染模型中的有效性和耐药性的发展。这项工作将利用金黄色葡萄球菌的遗传操作和等位基因交换，用RT-PCR测量基因表达，并利用基因组定义的甲氧西林耐药菌株和其他金黄色葡萄球菌建立小鼠感染模型(皮下脓肿、肾脓肿、致死性)。该计划项目的总体目标是采取一种整合良好的多学科方法来了解抗生素耐药性的发展和传播，并将这一努力与寻找通过抑制新的靶点和途径来危害耐药病原体的化合物相结合，包括甲氧西林耐药金黄色葡萄球菌(MRSA)。该项目将增加对与多药外排泵相关的耐药性机制的了解，并提供菌株以测试这种泵对抗新靶点和新途径的新化合物的影响。它还将利用常见MRSA感染的哺乳动物模型来测试化合物在体内的活性。

PROJECT SUMMARY (See Instructions): The longterm goals of the project are to identify the full array of efflux pumps of Staphylococcus aureus that contribute to multiple antimicrobial resistance and to elucidate the determinants of their expression, their role in microbial physiology and their effect on bacterial response to antimicrobials in infection. The work will focus on genetic analysis of regulatory elements and on bacterial fitness and response to antimicrobials in a subcutaneous abscess model, collaborating with other project groups to assess the efficacy of novel antimicrobial compounds in abscesses and the extent to which efflux pumps affect that efficacy. There are four specific aims: 1) assess the effects of NorB, NorD, and Tet38 efflux pumps and their regulators on response to antimicrobials in animal models of infection; 2) evaluate the regulation of expression of abcA encoding an ABC family efflux pump and assess its effects on membrane and cell wall-targeting agents; 3) analyze the global array of pumps over expressed in an abscess environment and determine their contribution to resistance to established agents and novel compounds; and 4) test novel compounds discovered in other subprojects of the program project for resistance to efflux pump expression and for efficacy and development of resistance in mammalian infection models. The work will utilize genetic manipulation and allelic exchange in S. aureus, measurements of gene expression with RT-PCR, and established murine models of infection (subcutaneous abscess, renal abscess, lethality) utilizing a genomically defined strains of methicillin resistant and other S. aureus. The overall goal of the program project is to take a well-integrated, multidisciplinary approach to understanding antibiotic resistance development and transmission, and to integrate that effort with the search for compounds that compromise resistant pathogens, including methicillin-resistant S. aureus (MRSA), by inhibiting novel targets and pathways. This project will add to understanding of resistance mechanisms related to multidrug efflux pumps and provide strains for testing the effect of such pumps on novel compounds active against new targets and pathways. It will also utilize mammalian models of a common MRSA infection to test compound activity in vivo.