Identification of Salmonella Genes Important for Systemic Colonization

描述(由申请人提供)：我们将使用完整基因组序列和正向遗传学的力量来识别允许细菌病原体在小鼠模型中定植系统器官的新基因。非伤寒沙门氏菌(NTS)是一种食源性细菌病原体，每年在全球范围内导致数亿例腹泻疾病和数十万人死于菌血症。肠沙门氏菌血清型鼠伤寒沙门氏菌是确定NTS系统感染需求的合适模型，因为该血清型比任何其他血清型导致更多的NTS菌血症病例，在5岁以下的儿童和HIV感染者中。全基因组序列信息的可获得性、遗传操作的简便性以及大量动物模型的可获得性使SEROT成为SEROT。小鼠是一个很好的模型系统.我们已经在SEROT中产生了1030个靶向缺失菌株的集合。鼠伤寒沙门氏菌(约占基因组的25%)，开发了一种新型的寡核苷酸微阵列来分析这一突变集合，并开始在体外和体内系统定植的小鼠模型中对该突变集合进行正向遗传筛选。我们希望完成这些工具的开发，并对系统定植所涉及的基因子集进行更全面的研究，这一过程发生在由这种生物引起的NTS菌血症期间。我们将通过以下步骤实现这一目标：1.完成我们在鼠伤寒沙门氏菌中所有非必需基因的缺失库；2.在小鼠模型中筛选我们的完整缺失库，以确定与系统定植有关的新基因；3.确认每个突变体对于系统定植是有缺陷的；4.鉴定在与培养的巨噬细胞结合、入侵和复制能力方面存在系统定植缺陷的突变体。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140万例腹泻疾病，是美国与病毒、寄生虫或细菌相关的食源性疾病最常见的死亡原因，主要发生在免疫功能低下的人中。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系统性感染。艾滋病在世界许多地区的上升，特别是在撒哈拉以南非洲，导致与非传染性疾病相关的系统性感染的频率急剧增加。该项目中描述的工作将为沙门氏菌感染引起的急性系统性疾病的疫苗和治疗提供新的目标。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.