Mechanisms Underlying Nutrient-Mediated Sporulation in C. difficile

项目摘要/摘要 艰难梭状芽胞杆菌(前称梭状芽孢杆菌)是引起严重腹泻的主要医院病原菌 一种传染性很强且难以治疗的疾病。艰难梭菌的形成和传播很容易 从受感染的宿主中排出高达108个孢子/毫升的粪便。艰难梭菌的孢子型对大多数 消毒剂，对细菌在宿主肠道外的生存至关重要。不幸的是，几乎没有 已知导致孢子形成的肠道信号。这项调查的长期目标是 揭示营养如何驱动艰难梭菌的致病和传播。这一行动的具体目标 应用是为了确定哪些不同的营养途径和效应物对孢子的影响最大 生产，以及这些影响是如何调节的。根据我们的数据，我们假设特定的肠道 代谢产物促进毒素表达和孢子形成，而其他代谢产物阻碍这些过程。 这些研究的基本原理是，揭示驱动孢子产生的营养线索 将帮助我们了解疾病和传播是如何发生的。在我们的初步研究中，我们发现了特定的 对艰难梭菌孢子形成有显著影响的营养物质。利用我们以前在 艰难梭菌的分子遗传学、代谢基因调控和革兰氏阳性肠道发病机制，我们将 通过在两个具体目标中详细说明的实验来达到目标。首先，我们将定义特定的 途径，然后评估影响艰难梭菌孢子的营养物质的影响 形成和传播。同时，我们将剖析将特定营养物质与 孢子形成。这项研究具有创新性，因为它利用了关于 支持CDI的肠道环境，并结合生化和遗传方法来回答 关于这一重要而复杂的生物过程的基本问题。这一项目的预期贡献 研究是对相关细菌途径的详细了解，这些途径使艰难梭菌在 对特定营养物质的反应。此外，这项工作是制定理性战略的重要一步。 通过防止宿主内形成有感染性的孢子来阻止艰难梭菌的传播。

Project Summary/Abstract Clostridioides difficile (formerly Clostridium) is a major nosocomial pathogen that causes severe diarrheal disease that is highly infectious and difficult to treat. C. difficile is easily transmitted due to the formation and expulsion of up to 108 spores/ml of stool from infected hosts. The spore form of C. difficile is resistant to most disinfectants and is critical for the survival of the bacterium outside of the host intestine. Unfortunately, little is known about the intestinal signals that lead to spore formation. The long-term goal of this investigation is to uncover how nutrition drives C. difficile pathogenesis and transmission. The specific objectives of this application are to determine which distinct nutritional pathways and effectors have the greatest impact on spore production, and how these effects are regulated. Based on our data, we hypothesize that specific intestinal metabolites promote toxin expression and spore formation, while other metabolites impede these processes. The rationale underlying these studies is that uncovering the nutritional cues that drive the production of spores will help us understand how disease and transmission occur. In our preliminary studies, we identified specific nutrients that have dramatic effects on C. difficile spore formation. Capitalizing on our previous experiences in C. difficile molecular genetics, metabolic gene regulation, and Gram-positive intestinal pathogenesis, we will meet the objectives through the experiments detailed in two specific aims. To begin, we will define the specific pathways affected by these compounds and then evaluate the impact of influential nutrients on C. difficile spore formation and transmission. In parallel, we will dissect the regulatory mechanisms that link specific nutrients to spore formation. This research is innovative because it takes advantage of the latest information about the intestinal environment that supports CDI, and combines biochemical and genetic approaches to answer fundamental questions about this important and complex biological process. The expected contribution of this research is a detailed understanding of the relevant bacterial pathways that enable C. difficile sporulation in response to specific nutrients. Moreover, this work is an essential step in the development of rational strategies to impede C. difficile transmission by preventing the formation of infectious spores in the host.