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.

艰难梭菌的毒素表达和孢子形成是特定环境的现象，整合了 来自周围环境的信号，包括肠道的局部营养环境。 该实验室的目标是确定细菌与细菌和宿主相互作用的机制基础 调节艰难梭菌的毒力 该提案的总体目标是 (i) 确定机制。 由耐万古霉素屎肠球菌产生的艰难梭菌生长的扩散抑制剂的研究 (VRE)和(ii)定义了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 通过多种背景依赖性调节艰难梭菌毒力 机制根据可用的碳源而变化 该项目的基本原理是： 确定两个物种之间相互作用的机制将有助于开发抗 限制 CDI 潜力的 VRE 治疗为实现总体目标，将实现这两​​个具体目标。 目标：目标 1) 确定 VRE 对艰难梭菌的碳源依赖性抑制机制。 根据初步数据，工作假设是：在存在转化的碳源的情况下 通过 VRE 将有机酸转化为有机酸，将艰难梭菌的生长抑制到低于 pH 阈值并控制碳 在这些实验中，体外来源和 VRE 定植动物中的来源将调节艰难梭菌的毒力。 确定的培养基将用于筛选一组碳源、肠球菌、乳酸菌和 艰难梭菌菌株以确定调节生长的条件，这些数据将用于开发 优化的 VRE-C 小鼠模型 目标 2) 定义与接触依赖性的相互作用。 VRE 抑制艰难梭菌孢子形成 根据初步数据，工作假设是： 在没有碳源的情况下，VRE 通过非扩散调节剂抑制艰难梭菌进入孢子形成 在这种状态下抑制孢子形成会增加艰难梭菌产生的毒素水平。 将使用培养测定和荧光显微镜来确定孢子形成的抑制是否有效 通过接触介导以及在哪个发育阶段孢子形成受到抑制 C. difficile 将用于确定孢子形成遗传程序的哪个部分受到 VRE 的影响。 申请人认为所提议的研究具有创新性，因为它专门关注 两种胃肠道病原体之间的相互作用以及肠道条件如何影响平衡 拟议的研究意义重大，因为它将提供一个背景。 了解艰难梭菌在 VRE 定植动物中的毒力潜力，这反映了常见的情况 这两种细菌在人类患者体内共同定殖。