Mechanisms of antibiotic efflux in Campylobacter

弯曲杆菌抗生素外流机制

• 批准号: 7360794
• 负责人: Qijing Zhang
• 金额: $ 10.28万
• 依托单位: IOWA STATE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-04-01 至 2007-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7360794
• 关键词: ATP-Binding Cassette Transporters; Animal Model; Animals; Antibiotic Resistance; Antibiotic Therapy; Antimicrobial Resistance; Bacteria; Bile fluid; Binding; Biochemical; C-terminal; Campylobacter; Campylobacter jejuni; Categories; Cell Survival; Child; Complex; Condition; DNA; DNA Binding Domain; Developed Countries; Developing Countries; Diarrhea; Effectiveness; Enteral; Environment; Family; Funding; Genes; Genomics; Goals; Grant; In Vitro; Intestines; Laboratories; Ligand Binding Domain; Mediating; Membrane Transport Proteins; Molecular; Molecular Genetics; Molecular Target; Multi-Drug Resistance; N-terminal; National Institute of Allergy and Infectious Disease; Organism; Oxygen; Oxygen measurement, partial pressure, arterial; Physiological; Physiological Processes; Physiology; Play; Poison; Positioning Attribute; Prohibit; Promoter Regions; Reagent; Regulation; Repression; Research Personnel; Resistance; Resources; Role; Structure; System; United States; Work; X-Ray Crystallography; antibiotic efflux; base; bile salts; design; dicarboxylate; dicarboxylate-binding protein; efflux pump; enteric pathogen; environmental change; fluoroquinolone resistance; foodborne; in vivo; mutant; novel; pathogen; prevent; programs; promoter; resistance mechanism; uptake

Bacterial antibiotic efflux transporters are important players in conferring intrinsic and acquired resistance to antimicrobials. Campylobacterjejuni, a leading bacterial cause of foodborne diarrhea in the United States and an agent included in the NIAID Category B Priority Pathogens list, harbors multiple antibiotic efflux transporters of different families. During the previous grant period, we determined the function and regulation of two efflux pumps (CmeABC and CmeDEF) of the resistance-nodulation-division (RND) family in Campylobacter. Our findings indicate that the efflux system not only contributes to antimicrobial resistance, but also has important physiological functions in facilitating Campylobacter colonization in the intestinal tract of animals. We have also found that CmeR, a transcriptional factor, represses cmeABC and that bile salts (normally present in the gut) induce the expression of cmeABC by inhibiting the binding of CmeR to the promoter of cmeABC. Our recent preliminary studies also strongly suggest that CmeR is a pleiotropic regulator and modulates the expression of the MF (major facilitator) and MATE (multidrug and toxic compound extrusion) transporters as well as the C4-dicarboxylate transporters potentially involved in Campylobacter adaptation to the oxygen-limited environment in animal intestine. These findings indicate that the antibiotic efflux system is co-regulated by CmeR with other physiological processes and plays important roles in antimicrobial resistance and in facilitating Campylobacter adaptation to environmental changes. Despite these recent advances, the majority of the CmeR-regulated efflux transporters in Campylobacter have not been functionally characterized, and the molecular mechanisms governing the expression of the transporters and the structural basis of CmeR regulation remain to be determined. To close these important gaps in our understanding of the active efflux system in Campylobacter, we plan to pursue 3 specific aims in this renewal application to 1) determine the regulatory mechanisms and functions of the MF and MATE transporters in C. jejuni, 2) define the regulation and role of the C4-dicarboxylate transport system in facilitating Campylobacter adaptation to oxygen-limited conditions, and 3) elucidate the structural basis of CmeR regulation and the mechanisms of bile induction using X-ray crystallography. The proposed studies take advantage of unique resources available in our laboratories and utilize contemporary molecular, genetic, and biochemical approaches as well as an established animal model. Once completed, the proposed work together with the studies conducted in the previous grant period will reveal novel information on the functions and regulatory mechanisms of antibiotic efflux transporters in bacteria. The findings will help to identify potential molecular targets for the control and treatment of antibiotic resistant Campylobacter.

细菌抗生素外排转运蛋白在赋予内在和获得性耐药性中起重要作用 抗生素。空肠弯曲杆菌是美国食源性腹泻的主要细菌原因 以及NIAID B类优先病原体列表中包含的病原体，具有多种抗生素外排 不同家庭的运输商。在上一个资助期内，我们确定了 两个外排泵（CmeABC和CmeDEF）的耐药-增殖-分裂（RND）家族， 弯曲杆菌我们的研究结果表明，外排系统不仅有助于抗菌药物耐药性， 而且在促进弯曲杆菌在肠道中定植方面具有重要的生理功能 动物。我们还发现，CmeR，一种转录因子，抑制cmeABC， （通常存在于肠道中）通过抑制CmeR与CmeABC的结合来诱导cmeABC的表达。 cmeABC的启动子。我们最近的初步研究也有力地表明，CmeR是一个多效性的， 调节因子并调节MF（主要促进因子）和MATE（多药和毒性）的表达 化合物挤压）转运蛋白以及C4-二羧酸转运蛋白可能参与 弯曲杆菌对动物肠道氧限制环境的适应。这些发现表明 抗生素外排系统与其他生理过程共同受CmeR调节， 在抗生素耐药性和促进弯曲杆菌适应环境变化中的作用。 尽管最近取得了这些进展，但弯曲杆菌中的大多数CmeR调节的外排转运蛋白仍是不稳定的。 还没有功能上的特点，和分子机制的表达， 转运蛋白和CmeR调节的结构基础仍有待确定。关闭这些重要的 我们对弯曲杆菌主动外排系统的理解存在差距，我们计划追求3个具体目标， 本续期申请旨在：1）确定MF和MATE的监管机制和功能 C.空肠，2）定义C4-二羧酸转运系统的调节和作用， 促进弯曲杆菌适应氧气有限的条件，和3）阐明结构 CmeR调节的基础和胆汁诱导的机制，使用X射线晶体学。的 拟议的研究利用我们实验室的独特资源， 分子、遗传和生物化学方法以及已建立的动物模型。一旦完成， 拟议的工作加上上一个资助期进行的研究将揭示新颖的内容 关于细菌中抗生素外排转运蛋白的功能和调节机制的信息。的 这些发现将有助于确定控制和治疗抗生素耐药性的潜在分子靶点。 弯曲杆菌