Identification of Salmonella Genes Important for Systemic Colonization

描述（由申请人提供）：我们将使用全基因组序列和正向遗传学的力量来鉴定允许细菌病原体在小鼠模型中定植全身器官的新基因。非伤寒沙门氏菌（NTS）是食源性细菌病原体，每年在全世界造成数亿例腹泻病例和数十万例菌血症死亡。肠炎沙门氏菌血清型鼠伤寒沙门氏菌是确定NTS系统性感染需求的合适模型，因为该血清型在5岁以下儿童和艾滋病毒感染者中引起的NTS菌血症病例比任何其他血清型都多。全基因组序列信息的可用性，基因操作的便捷性，以及大量动物模型的可用性使其变得更加重要。鼠伤寒是一个很好的模型系统。我们在serot中生成了1030个目标缺失菌株的集合。鼠伤寒（约占基因组的25%），开发了一种新的寡核苷酸微阵列来检测这些突变体，并开始在体外和体内的小鼠模型中对这些突变体进行遗传筛选。我们希望完成这些工具的开发，并对参与系统定植的基因子集进行更全面的研究，这一过程发生在由该生物体引起的NTS菌血症期间。我们将通过以下途径实现这一目标：完成鼠伤寒沙门菌所有非必需基因的缺失文库。在小鼠模型中筛选我们的完全缺失集合，以确定参与系统定植的新基因。4.确认每个突变体在系统定植中存在缺陷。描述了在培养巨噬细胞中与巨噬细胞结合、侵入和复制能力有缺陷的突变体。公共卫生相关性：沙门氏菌是食源性疾病的主要原因，每年导致约140万例腹泻病，是美国与病毒、寄生虫或细菌相关的食源性疾病的最常见死亡原因，主要发生在免疫功能低下的人群中。在幼儿和艾滋病毒感染者中，非伤寒沙门氏菌（NTS）经常引起与高死亡率相关的全身感染。艾滋病在世界许多地区，特别是撒哈拉以南非洲地区的上升，导致nts相关全身感染的频率急剧增加。本项目所描述的工作将为沙门氏菌感染引起的急性全系统疾病的疫苗和治疗提供新的靶点。这项工作将对公众健康产生直接影响。

DESCRIPTION (provided by applicant): We will use the power of complete genome sequences and forward genetics to identify novel genes that allow a bacterial pathogen to colonize systemic organs in murine models. Non-typhoidal Salmonella (NTS) are food-borne bacterial pathogens that cause hundreds of millions of cases of diarrheal disease and hundreds of thousands of deaths due to bacteremia annually worldwide. Salmonella enterica serotype Typhimurium is an appropriate model to determine the requirements for systemic infection by NTS as this serotype causes more cases of NTS bacteremia, in children under the age of 5 and in HIV infected individuals, than any other serotype. The availability of complete genome sequence information, the ease of genetic manipulation, and the availability of numerous animal models make serot. Typhimurium an excellent model system. We have generated a collection of 1030 targeted deletion strains in serot. Typhimurium (approximately 25% of the genome), developed a novel oligonucleotide microarray to assay this collection of mutants, and begun forward genetic screening of this mutant collection both in vitro and in vivo in murine models of systemic colonization. We wish to complete the development of these tools and progress to more comprehensive studies of a subset of genes involved in systemic colonization a process that occurs during NTS bacteremia caused by this organism. We will approach this goal by: 1. Completion of our deletion library in all non-essential genes in Salmonella Typhimurium, 2. Screening our complete deletion collection in murine models to identify new genes involved in systemic colonization, 3. Confirming each mutant as defective for systemic colonization, 4. Characterizing mutants that are defective for systemic colonization for their ability to associate with, invade, and replicate in cultured macrophages. PUBLIC HEALTH RELEVANCE: Salmonella is a leading cause of food borne illness, causing ~1.4 million cases of diarrheal disease per year and is the single most common cause of death from food-borne illnesses associated with viruses, parasites or bacteria in the US primarily in immunocompromised persons. In young children and HIV-infected individuals, non-typhoidal Salmonellae (NTS) frequently cause systemic infection that is associated with high mortality. The rise of AIDS in many parts of the world, notably in sub- Saharan Africa, has resulted in a dramatic increase in the frequency of NTS-associated systemic infections. The work described in this project will provide novel targets for vaccines and treatments for acute systemic disease that results from Salmonella infection. This work will have a direct impact on public health.