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金黄色葡萄球菌的全系列外排泵，这些外排泵有助于多种抗菌药物耐药性，并阐明其表达的决定因素，其在微生物生理学中的作用及其对感染中细菌对抗菌药物的反应的影响。这项工作将侧重于调控元件的遗传分析，以及皮下脓肿模型中的细菌适应性和对抗菌剂的反应，与其他项目组合作评估新型抗菌化合物在脓肿中的疗效以及外排泵影响该疗效的程度。有四个具体目标：1）评估NorB、诺德和Tet 38外排泵及其调节剂对感染动物模型中抗微生物剂应答的影响; 2）评估编码ABC家族外排泵的abcA表达的调节并评估其对膜和细胞壁靶向剂的影响; 3）分析在脓肿环境中过度表达的泵的全局阵列，并确定它们对已建立的药剂和新化合物的抗性的贡献;和4）测试在该计划项目的其它子项目中发现的新化合物对外排泵表达的抗性以及在哺乳动物感染模型中的效力和抗性的发展。这项工作将利用遗传操作和等位基因交换在S。金黄色葡萄球菌，用RT-PCR测量基因表达，并利用基因组学定义的耐甲氧西林和其他S.金黄色。该计划项目的总体目标是采取一种综合的、多学科的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损害耐药病原体的化合物相结合，包括耐甲氧西林的S。金黄色葡萄球菌（MRSA），通过抑制新的目标和途径。该项目将增加对与多药外排泵相关的耐药机制的理解，并提供菌株用于测试此类泵对新靶点和途径的新型活性化合物的影响。它还将利用常见MRSA感染的哺乳动物模型来测试化合物的体内活性。

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.