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.

项目概要/摘要 多重药物和广泛耐药的革兰氏阴性菌的出现是一个日益严重的问题， 鲍曼不动杆菌是一种严重威胁的病原体 鲍曼不动杆菌因其快速产生多重耐药性而臭名昭著，会导致医院获得性感染， 在美国，估计有 60% 是医院获得性感染，表现为菌血症、尿路感染和伤口感染。 鲍曼不动杆菌感染具有多重耐药性，通常包括碳青霉烯类耐药性，这使得粘菌素成为 然而，粘菌素耐药性也已出现。 促进鲍曼不动杆菌抗生素耐药性的内在机制，以了解替代抗菌药物 我们的初步工作已经确定了两种可促进粘菌素耐药性的 LD 转肽酶。 脂寡糖缺陷鲍曼不动杆菌，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，其中替代交联弥补了外膜缺陷。 提案中，我们将解决三个重要问题，以了解 LD-转肽酶的功能和调控 在鲍曼不动杆菌中，包括 (I) LD-转肽酶活性如何对抗其他裂解机械力 由外膜缺陷产生？；（II）鲍曼不动杆菌中 LdtK 脂蛋白底物是如何调节的？ A 类青霉素结合蛋白如何影响鲍曼不动杆菌中的 LD 转肽酶活性？ 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 建立了鲍曼不动杆菌中导致多药耐药性的内在因素模型。 将有助于设计针对必需外膜和肽聚糖的组合药物方案 细胞膜层，从而排除耐药性；因此，我们的研究结果支持国家 健康研究所的使命，旨在促进减少人类疾病的基本发现。