Mechanistic basis of how LD-transpeptidases protect against outer membrane defects

LD-转肽酶如何防止外膜缺陷的机制基础

• 批准号: 10586069
• 负责人: Joseph Michael Boll
• 金额: $ 28.87万
• 依托单位: UNIVERSITY OF TEXAS ARLINGTON
• 依托单位国家: 美国
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-03-08 至 2023-09-01
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10586069
• 关键词: Abbreviations; Acinetobacter baumannii; Affect; Antibiotic Resistance; Antibiotic Therapy; Antibiotics; Antimicrobial susceptibility; Bacteremia; Bacterial Physiology; Biogenesis; Carbapenems; Carboxypeptidase; Cell Shape; Cell Wall; Cell model; Cells; Centers for Disease Control and Prevention (U.S.); Cessation of life; Colistin; Compensation; Cytoprotection; Defect; Development; Enzyme Activation; Enzymes; Escherichia coli; Fostering; Glucosyltransferase; Goals; Gram-Negative Bacteria; Growth; Hospitals; Human; Immunoprecipitation; Infection; Intrinsic factor; Knowledge; Laboratories; Life; Link; Lipoproteins; Lytic; Measures; Mechanics; Membrane; Mission; Modeling; Modification; Molecular Weight; Multi-Drug Resistance; Nosocomial Infections; Osmotic Shocks; Penicillin-Binding Proteins; Peptidoglycan; Peptidyltransferase; Pharmaceutical Preparations; Phenotype; Physiology; Polymyxins; Property; Public Health; Refractory; Regimen; Regulation; Reporting; Resistance; Role; Stress; Structure; Superbug; System; Testing; Therapeutic; Treatment Failure; Treatment Protocols; United States National Institutes of Health; Urinary tract; Vesicle; Work; World Health Organization; Wound Infection; antimicrobial; biological adaptation to stress; carbapenem resistance; cell envelope; colistin resistance; combat; combinatorial; crosslink; design; extensive drug resistance; fortification; glycosyltransferase; human disease; improved; lipooligosaccharide; mechanical force; mechanical load; molecular modeling; pathogen; resistance gene; resistance mechanism; response; treatment strategy

Project Summary/Abstract The emergence of multidrug and extensively drug-resistant Gram-negative bacteria is a growing problem that threatens established antimicrobial treatment protocols. Acinetobacter baumannii is a critical threat pathogen notorious for its ability to rapidly develop multidrug resistance. A. baumannii causes hospital-acquired infections, which manifest as bacteremia, urinary tract and wound infections. In the US, an estimated 60% of hospital-acquired A. baumannii infections were multidrug-resistant, often including carbapenem resistance, which leaves colistin as the “last-resort” treatment option. However, colistin resistance has also emerged. There is an urgent need to understand intrinsic mechanisms that promote antibiotic resistance in A. baumannii to guide alternative antimicrobial strategies. Our preliminary work has identified two LD-transpeptidases that promote viability of colistin resistant lipooligosaccharide-deficient A. baumannii. Specifically, LD-transpeptidase-dependent cell envelope modifications are key for the resistance phenotype, where alternative crosslinks compensate for outer membrane defects. In this proposal, we will address three important questions to understand the function and regulation of LD-transpeptidases in A. baumannii, including (I) how does LD-transpeptidase activity counter otherwise lytic mechanical forces produced by outer membrane defects?; (II) how are LdtK lipoprotein substrates regulated in A. baumannii?; and (III) how do class A penicillin-binding proteins impact LD-transpeptidase activity in A. baumannii? Collectively, these studies will address key questions in bacterial physiology and cell envelope assembly, which will enable us to build a model of intrinsic factors in A. baumannii that contribute to multidrug resistance. Furthermore, these analyses will aid in the design of combinatorial drug regimens that target both essential outer membrane and peptidoglycan layers of the cell envelope, thus precluding resistance; consequently, our findings support the National Institute of Health mission, which aims to foster fundamental discoveries to reduce human disease.

项目总结/摘要 多重耐药和广泛耐药革兰氏阴性菌的出现是一个日益严重的问题， 威胁到既定的抗菌治疗方案。鲍曼不动杆菌是一种严重威胁的病原体 因其快速产生多药耐药性的能力而臭名昭著。A.鲍曼不动杆菌引起医院获得性感染， 表现为菌血症、尿路和伤口感染。在美国，估计有60%的医院获得性 A.鲍曼不动杆菌感染是多重耐药的，通常包括碳青霉烯类耐药，这使得粘菌素作为 “最后一招”治疗方案。然而，也出现了粘菌素耐药性。迫切需要 了解促进A.鲍曼不动杆菌指导替代抗菌药物 战略布局我们的初步工作已经确定了两个LD-转肽酶，促进粘菌素耐药的生存力， 脂寡糖缺乏型A.鲍曼不动杆菌。具体而言，LD-转肽酶依赖性细胞包膜修饰 是耐药表型的关键，其中替代交联补偿外膜缺陷。在这 建议，我们将解决三个重要问题，以了解LD-转肽酶的功能和调节 以.鲍曼不动杆菌，包括（I）LD-转肽酶活性如何对抗其他溶解性机械力 由外膜缺陷产生的？(II)LdtK脂蛋白底物在A.鲍曼不动杆菌？和（III） A类青霉素结合蛋白如何影响A. baumannii？总的来说，这些 研究将解决细菌生理学和细胞包膜组装中的关键问题，这将使我们能够 建立了A.导致多重耐药性的鲍曼不动杆菌。此外，这些分析 将有助于设计靶向必需外膜和肽聚糖的组合药物方案 细胞被膜的层，从而排除阻力;因此，我们的研究结果支持国家 卫生研究所的使命，旨在促进基本发现，以减少人类疾病。