Biological vector borne transmission of Salmonella by cockroaches

项目摘要 德国小蠊（Blattella germanica）是人类最常见的蟑螂 环境. B。德国葡萄球菌有助于传播引起肠道（腹泻）疾病的细菌， 包括鼠伤寒沙门氏菌，但其传播机制尚不清楚 明白蟑螂的肠道细菌病原体传播以前曾被描述为 机械性质。机械传播是细菌从一个位置被动的、非复制性的转移 或宿主。相对于主动生物传播，这种机制的影响有限。但最近的 我们实验室的数据表明，S.德国小蠊的鼠伤寒沙门氏菌 比简单的机械传播更复杂，而是类似于其他昆虫的生物传播 从受感染的宿主中摄取细菌，然后定居下来， 和传输。特别是，我们已经观察到，摄入后，S。鼠伤寒的生活方式 德国小蠊消化道的变化和多重复制事件。此外，我们有 发现了几个S。细菌定植和肠道脱落所必需的鼠伤寒杆菌基因 的B。germanica，证明细菌的活跃作用。拟议研究项目的中心目标 目的是深入了解沙门氏菌的生物媒介传播机制。鼠伤寒 被德国蟑螂咬了提出了三个独立的具体目标。首先，我们要阐明 野生型S.鼠伤寒杆菌在若虫和成虫中的定殖和脱落。 第二，利用一系列无与伦比的突变S。鼠伤寒菌株，我们将确定特定的细菌 基因和功能是蟑螂定植和随后传播所必需的。三是 将确定两个关键的宿主因素，即抗菌效应和肠道微生物群，对S。 鼠伤寒定殖和散毒。总之，拟议的研究将建立一个图片，细菌如何 与宿主因子相互作用，形成了S.鼠伤寒沙门氏菌的德国蟑螂，提供 对一个独特的、研究不足的病媒-病原体系统的动力学的基本见解， 分布和公共卫生影响。

PROJECT SUMMARY The German cockroach, Blattella germanica, is the most common pestiferous cockroach species in human environments. B. germanica contributes to the transmission of bacteria that cause enteric (diarrheal) disease, including Salmonella enterica serovar Typhimurium, but the mechanisms of transmission are not well understood. Enteric bacterial pathogen transmission by cockroaches has previously been described as mechanical in nature. Mechanical transmission is a passive, non-replicative transfer of bacteria from one location or host to another. This mechanism is limited in impact relative to active biological transmission. However, recent data from our laboratory indicate that transmission of S. Typhimurium by German cockroaches is markedly more complex than simple mechanical transmission and instead resembles biological transmission by other insects that intake bacteria from infected hosts and are subsequently colonized, enabling active and prolonged shedding and transmission. In particular, we have observed that following ingestion, S. Typhimurium undergoes a lifestyle change and multiple replication events in the digestive tract of the German cockroach. Furthermore, we have identified several S. Typhimurium genes that are necessary for bacterial colonization and shedding from the gut of B. germanica, evidencing an active role of the bacteria. The central objective of the proposed research project is to gain a detailed understanding of the mechanisms of biological vector-borne transmission of S. Typhimurium by the German cockroach. Three independent specific aims are proposed. First, we will elucidate the fine spatiotemporal details of wild-type S. Typhimurium colonization and shedding in nymph and adult cockroaches. Second, leveraging an unparalleled array of mutant S. Typhimurium strains, we will identify specific bacterial genes and functions that are necessary for colonization of cockroaches and subsequent transmission. Third, we will determine the effects of two key host factors, namely antimicrobial effectors and the gut microbiota, on S. Typhimurium colonization and shedding. Together, the proposed studies will establish a picture of how bacterial and host factors interact to shape biological transmission of S. Typhimurium by the German cockroach, providing fundamental insight into the dynamics of a unique, poorly studied vector-pathogen system with a global distribution and public health impact.