Role and regulation of a peptidoglycan synthesis enzyme required for cephalosporin resistance in enterococci

肠球菌头孢菌素耐药所需肽聚糖合成酶的作用和调节

• 批准号: 10324562
• 负责人: Carly Mascari
• 金额: $ 4.68万
• 依托单位: MEDICAL COLLEGE OF WISCONSIN
• 依托单位国家: 美国
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-01-01 至 2022-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10324562
• 关键词: Address; Antibiotic Resistance; Antibiotics; Bacteremia; Bacteria; Blood Circulation; Cell Wall; Cells; Centers for Disease Control and Prevention (U.S.); Cephalosporin Resistance; Cephalosporins; Cessation of life; Collaborations; Communication; Competence; Complement; Complication; Critical Illness; Cytolysis; Data; Development; Disease; Endocarditis; Enterococcus; Enterococcus faecalis; Enterococcus faecium; Enzymes; Fellowship; Goals; Health; Health Care Costs; Healthcare; Heart Valves; Human; Immunocompromised Host; Infection; Infective endocarditis; Institution; Intrinsic drive; Link; Mediating; Mentors; Microbe; Microbial Biofilms; Molecular; Multi-Drug Resistance; Peptidoglycan; Phosphoric Monoester Hydrolases; Phosphorylation; Phosphotransferases; Prevention; Proliferating; Regulation; Resistance; Resources; Risk Factors; Role; Scientist; Sepsis; Signal Transduction; Stress; Suppressor Mutations; Training; Vancomycin resistant enterococcus; Work; base; career; clinically relevant; crosslink; design; experimental study; gain of function mutation; improved; inhibitor; insight; medical schools; mortality; mutant; novel; novel therapeutics; overexpression; prevent; protein function; protein protein interaction; resistance mechanism; resistant strain; response; skills; therapeutic development

PROJECT SUMMARY/ABSTRACT: Infective endocarditis, a condition in which bacteria grow in a biofilm-like state on the valves of the heart, is a deadly complication of bloodstream infections. Enterococcus species are responsible for 30% of healthcare- acquired endocarditis. When caused by multi-drug resistant strains, such as vancomycin-resistant enterococci (VRE), infective endocarditis is nearly untreatable and uniformly fatal. The CDC considers VRE a serious threat and estimates 5,400 VRE-related deaths and over $500 million in associated healthcare costs in 2017. A major risk factor for the development of enterococcal endocarditis and other infections is prior treatment with cephalosporin antibiotics. The two most clinically relevant species of Enterococcus, E. faecalis and E. faecium, are intrinsically resistant to cephalosporins. Treatment with cephalosporin antibiotics allows commensal enterococci to proliferate and disseminate to the bloodstream, a prerequisite for infection of the heart valves. The goal of this project is to further our understanding of molecular mechanisms of cephalosporin resistance in enterococci. This understanding will enable development of new therapies that both reduce the occurrence of enterococcal infections and improve treatment options to overcome recalcitrant endocardial infections. Specifically, a novel link will be investigated between two known cephalosporin resistance determinants, IreK and MurAA. IreK is a kinase that is thought to sense and respond to cell wall stress, including that caused by inhibition of peptidoglycan crosslinking upon cephalosporin treatment. However, the targets of IreK signaling that facilitate this response, and ultimately cephalosporin resistance, are largely unknown. MurAA, an enzyme that catalyzes the first committed step in peptidoglycan synthesis is also required for cephalosporin resistance. The central hypothesis of this project is that MurAA is a downstream target of IreK signaling, such that regulation of MurAA is one mechanism by which IreK controls cephalosporin resistance. Preliminary evidence suggests that this regulation is mediated by the known IreK-phosphorylation substrate, IreB. This hypothesis will be addressed in two aims. Aim 1 will determine how IreB and IreK signaling impact functions of MurAA. Aim 2 will identify MurAA interaction partners and determine the functional consequences of these interactions. Preliminary data suggest that a protein-protein interaction is important for either facilitating or regulating functions of MurAA. This work will be conducted at the Medical College of WI under the sponsorship of Dr. Christopher Kristich. The sponsor and institution are well-equipped to provide resources and support for this fellowship. In collaboration with the sponsor, the candidate has designed a training plan that complements this project. The training plan supports development of broad technical, communication and mentoring skills and encourages the professional development of the candidate. Development of these competencies will catalyze a successful career for the candidate as a well-rounded, independent scientist investigating microbes in human health and disease.

项目概要/摘要： 感染性心内膜炎是一种细菌在心脏瓣膜上以生物膜样状态生长的疾病。 血流感染的致命并发症。肠球菌属物种负责 30% 的医疗保健 - 获得性心内膜炎。当由多重耐药菌株引起时，例如耐万古霉素肠球菌 (VRE)，感染性心内膜炎几乎无法治愈，而且都是致命的。 CDC 认为 VRE 是严重威胁 并估计 2017 年有 5,400 人死于 VRE 相关死亡，相关医疗费用超过 5 亿美元。 发生肠球菌性心内膜炎和其他感染的危险因素是事先接受以下治疗 头孢菌素类抗生素。临床上最相关的两种肠球菌，粪肠球菌和屎肠球菌， 对头孢菌素具有内在耐药性。头孢菌素类抗生素治疗可实现共生 肠球菌增殖并传播到血流中，这是心脏瓣膜感染的先决条件。 该项目的目标是进一步了解头孢菌素耐药的分子机制 肠球菌。这种理解将有助于开发新疗法，以减少以下疾病的发生： 肠球菌感染并改善治疗方案以克服顽固性心内膜感染。 具体来说，将研究两个已知头孢菌素耐药决定因素 IreK 之间的新联系 和穆尔AA。 IreK 是一种激酶，被认为可以感知和响应细胞壁应激，包括由 头孢菌素治疗后肽聚糖交联的抑制。然而，IreK 的目标信号表明 促进这种反应以及最终头孢菌素耐药性的机制在很大程度上尚不清楚。 MurAA，一种酶， 催化肽聚糖合成的第一个关键步骤也是头孢菌素耐药性所必需的。这 该项目的中心假设是 MurAA 是 IreK 信号传导的下游靶标，因此调节 MurAA 是 IreK 控制头孢菌素耐药性的一种机制。初步证据表明 这种调节是由已知的 IreK 磷酸化底物 IreB 介导的。这个假设将得到解决 有两个目标。目标 1 将确定 IreB 和 IreK 信号传导如何影响 MurAA 的功能。目标 2 将确定 MurAA 相互作用伙伴并确定这些相互作用的功能后果。初步数据 表明蛋白质-蛋白质相互作用对于促进或调节 MurAA 的功能很重要。 这项工作将在 Christopher Kristich 博士的赞助下在威斯康星州医学院进行。这 赞助商和机构有能力为该奖学金提供资源和支持。合作中 候选人与赞助商一起设计了一个补充该项目的培训计划。培训计划 支持广泛的技术、沟通和指导技能的发展，并鼓励专业人士 候选人的发展。这些能力的发展将促进职业生涯的成功 候选人作为一名全面、独立的科学家，研究人类健康和疾病中的微生物。