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产孢是结合在一起的特定环境现象