New understanding of LTA as a determinant of daptomycin susceptibility in VRE E. faecium

对 LTA 作为 VRE 屎肠球菌达托霉素敏感性决定因素的新认识

• 批准号: 9926227
• 负责人: Michael S Gilmore
• 金额: $ 21.25万
• 依托单位: MASSACHUSETTS EYE AND EAR INFIRMARY
• 依托单位国家: 美国
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-05-07 至 2023-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9926227
• 关键词: Anabolism; Antibiotics; Back; Binding; Boston; Cardiolipins; Cell Wall; Cell membrane; Corpus striatum structure; Corynebacterium; Daptomycin; Data; Defect; ESKAPE pathogens; Enterococcus; Enterococcus faecium; Enzymes; Exhibits; Genes; Genetic Polymorphism; Glycopeptides; Goals; Homologous Gene; Hospitals; Infection; Investigation; Lead; Left; Lesion; Membrane; Modeling; Modification; Multi-Drug Resistance; Mutate; Mutation; Nosocomial Infections; Pathway interactions; Peptidoglycan; Pharmaceutical Preparations; Pharmacotherapy; Phenotype; Phosphatidylglycerols; Phospholipids; Physiological; Postdoctoral Fellow; Predisposition; Production; Research; Resistance; Staphylococcus aureus; Stress; Teichoic Acids; Testing; Urinary tract; Urinary tract infection; Vancomycin Resistance; Vancomycin resistant enterococcus; Work; acronyms; antimicrobial resistant infection; bactericide; base; biological adaptation to stress; cardiolipin synthase; experimental study; gain of function mutation; graduate student; lipoteichoic acid; loss of function mutation; mutant; prevent; resistant strain; response; stem

Project summary: Enterococci are leading causes of multidrug resistant hospital acquired infection – the first E in the ESKAPE acronym. Most E. faecium isolates at major centers are vancomycin resistant (VRE), and daptomycin is often the last line bactericidal drug for treatment. Unfortunately, daptomycin resistance is increasingly common, and can arise during treatment. Here we discovered a new vulnerability of VRE that appears to be related to production of membrane anchored lipoteichoic acid (LTA). A naturally occurring E. faecium mutant in this pathway, isolated from an infected urinary tract, exhibited hypersusceptibility to daptomycin, with a 20-fold lower MIC to this key drug. We developed preliminary data to show that this stemmed from a mutation in a gene termed lafB, which encodes an enzyme that make the immediate precursor glycopeptide onto which LTA is built. When selecting for revertants to the wild type level of daptomycin susceptibility or greater, we observed that lafB was always the first to mutate back, indicating that it may be dominant to other mutations that result in daptomycin resistance. If so, inhibition of lafB would have the potential to undo daptomycin resistance by other mechanisms, or at minimum, prevent those mutations from arising during treatment. The following proposal outlines a rigorous set of experiments to explore this new determinant of daptomycin susceptibility.

项目概要： 肠球菌是多重耐药性医院获得性感染的主要原因——第一个 E ESKAPE 缩写。主要中心的大多数屎肠球菌分离株均具有万古霉素耐药性 (VRE)， 而达托霉素往往是治疗的最后一线杀菌药物。不幸的是，达托霉素 耐药性越来越普遍，并且可能在治疗过程中出现。在这里我们发现了一个新的 VRE 的脆弱性似乎与膜锚定脂磷壁的产生有关 酸（LTA）。该途径中天然存在的屎肠球菌突变体，从感染者中分离出来 泌尿道，对达托霉素表现出高度敏感性，对该关键药物的 MIC 低 20 倍。 我们开发的初步数据表明，这是由一个名为 lafB 的基因突变引起的， 它编码一种酶，该酶可以产生 LTA 所在的直接前体糖肽 建造的。当选择达托霉素敏感性水平或更高的野生型回复体时， 我们观察到 lafB 总是第一个突变回来，这表明它可能在 其他导致达托霉素耐药性的突变。如果是这样，抑制 lafB 将具有 通过其他机制消除达托霉素耐药性的潜力，或至少预防那些 治疗期间出现的突变。以下提案概述了一套严格的 实验探索达托霉素敏感性的新决定因素。