Context-specific modulation of Clostridioides difficile virulence by Vancomycin-resistant Enterococcus faecium

耐万古霉素屎肠球菌对艰难梭菌毒力的特定调节

• 批准号: 10629341
• 负责人: Peter T McKenney
• 金额: $ 15.02万
• 依托单位: STATE UNIVERSITY OF NY,BINGHAMTON
• 依托单位国家: 美国
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-06-01 至 2025-05-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10629341
• 关键词: Acids; Affect; Agriculture; Animals; Antibiotic Resistance; Antibiotic Therapy; Antibiotics; Bacteria; Biological Assay; Carbon; Centers for Disease Control and Prevention (U.S.); Classification; Clinical; Clostridium difficile; Coculture Techniques; Data; Development; Disease; Enterococcus; Enterococcus faecium; Environment; Equilibrium; Fluorescence Microscopy; Genetic; Goals; Growth; Hospitalization; Human; In Vitro; Infection; Intestines; Laboratories; Left; Mediating; Metabolic; Microbe; Microscopy; Mission; Mus; National Institute of Allergy and Infectious Disease; Nature; Nutrient; Outcome; Patients; Probiotics; Production; Public Health; Recording of previous events; Regulation; Reporting; Research; Risk; Severities; Signal Transduction; Source; Systemic infection; Testing; Therapeutic; Toxin; Treatment Protocols; Vancomycin resistant enterococcus; Virulence; co-infection; experimental study; forgetting; gastrointestinal; gastrointestinal bacteria; genetic selection; gut colonization; gut microbiota; inhibitor; innovation; lactic acid bacteria; member; mortality; mouse model; organic acid; pathogen; pathogenic bacteria; programs; sugar; trait

Toxin expression and sporulation by Clostridioides difficile are context-specific phenomena that integrate signals from the surrounding environment including the local nutrient milieu of the intestine. The long-term goal of this laboratory is to define the mechanistic basis of bacteria-bacteria and host interactions that modulate virulence of C. difficile. The overall objectives in this proposal are to (i) determine the mechanism of a diffusible inhibitor of C. difficile growth produced by Vancomycin-resistant Enterococcus faecium (VRE) and (ii) define the mechanism of a contact-dependent inhibition of C. difficile sporulation by VRE. The central hypothesis is that VRE modulates C. difficile virulence by multiple context-dependent mechanisms that vary depending on the available carbon source. The rationale for this project is that determination of mechanisms of interaction between the two species will allow the development of anti- VRE treatments that limit the potential for CDI. To attain the overall objectives these two specific aims will be pursued: Aim 1) Identify the mechanism of carbon source-dependent suppression of C. difficile by VRE. Based on preliminary data, the working hypothesis is: in the presence of carbon sources that are converted to organic acids by VRE, C. difficile growth is suppressed below a pH threshold and manipulation of carbon sources in vitro and in VRE colonized animals will modulate C. difficile virulence. In these experiments a defined medium will be used to screen a panel of carbon sources, enterococci, lactic acid bacteria and C.difficile strains to determine conditions modulate growth and these data will be used to develop an optimized mouse model of VRE-C. difficile infection. Aim 2) Define the contact-dependent interaction with VRE that inhibits sporulation by C. difficile. Based on preliminary data, the working hypothesis is: in the absence of a carbon source, VRE inhibits entry into sporulation by C. difficile by a non-diffusible modulator and inhibition of sporulation in this state will increase the level of toxin produced by C. difficile. In these co- culture assays and fluorescence microscopy will be used to determine if the suppression of sporulation is mediated by contact and at what developmental stage sporulation is suppressed. Genetic selection in C. difficile will be used to determine which component of the sporulation genetic program is affected by VRE. The research proposed is innovative in the applicant’s opinion because it focuses specifically on interactions between two gastrointestinal pathogens and how conditions in the gut influence the balance between virulence traits. The proposed research is significant because it will provide a context for understanding the potential for C. difficile virulence in VRE-colonized animals, which mirrors the frequent co-colonization by these two bacteria in human patients.

梭状芽孢杆菌艰难梭菌的毒素表达和孢子是上下文特异性的现象 来自周围环境的信号，包括肠道的当地营养环境。长期 该实验室的目标是定义细菌 - 细菌和宿主相互作用的机械基础 调节艰难梭菌病毒。该提案的总体目标是（i）确定机制 抗性霉素肠球菌产生的艰难梭菌生长的扩散抑制剂 （VRE）和（ii）定义了通过VRE对艰难梭菌孢子形成的接触依赖性抑制的机制。 中心假设是，VRE通过多个上下文依赖性调节艰难梭菌病毒 取决于可用的碳源的机制。这个项目的理由是 确定两种物种之间相互作用的机制将允许发展 限制CDI潜力的VRE处理。为了实现总体目标，这两个具体目标将 被追捕：目标1）确定VRE对艰难梭菌抑制碳源依赖的机理。 基于初步数据，工作假设是：在存在转换的碳源的情况下 通过VRE到有机酸，艰难梭菌的生长被抑制在pH阈值以下和碳操纵下 体外和VRE定植的动物的来源将调节艰难梭菌病毒。在这些实验中 定义的培养基将用于筛选一组碳源，肠球菌，乳酸细菌和 C.缺乏菌株以确定条件调节生长，这些数据将用于开发 VRE-C的优化鼠标模型。艰难的感染。目标2）定义与接触的相互作用 VRE抑制艰难梭菌的孢子形成。基于初步数据，工作假设是： 缺乏碳源，VRE抑制了不可扩散调节器艰难梭菌孢子的孢子形成 在这种状态下的孢子形成将增加艰难梭菌产生的毒素水平。在这些共同 培养测定和荧光显微镜将用于确定孢子形成是否是 通过接触和在哪个发育阶段孢子形成介导。 C中的遗传选择。 艰难梭菌将用于确定孢子遗传程序的哪个组成部分受VRE的影响。 申请人认为，提出的研究具有创新性，因为它专门针对 两种胃肠道病原体之间的相互作用以及肠道中的状况如何影响平衡 在病毒特征之间。拟议的研究很重要，因为它将为 了解艰难梭菌病毒在VRE殖民化动物中的潜力，这反映了频率 这两种细菌在人类患者中共同殖民化。