Identification of Salmonella Genes Important for Systemic Colonization

描述（由申请人提供）：我们将利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殖全身器官的新基因。非伤寒沙门氏菌（NTS）是食源性细菌病原体，每年在全球范围内导致数亿例腹泻病和数十万例因菌血症而死亡。肠道沙门氏菌血清型鼠伤寒沙门氏菌是确定NTS全身感染要求的适当模型，因为该血清型在5岁以下儿童和HIV感染个体中引起的NTS菌血症病例多于任何其他血清型。全基因组序列信息的可用性、遗传操作的容易性以及大量动物模型的可用性使得血清素成为可能。鼠伤寒是一个很好的模型系统.我们已经在血清中产生了1030个靶向缺失菌株的集合。鼠伤寒沙门氏菌（约25%的基因组），开发了一种新的寡核苷酸微阵列，以测定该突变体的集合，并开始在体外和体内的小鼠模型的系统性定植的突变体集合的正向遗传筛选。我们希望完成这些工具的开发，并对参与系统性定植的基因子集进行更全面的研究，这一过程发生在这种生物体引起的NTS菌血症期间。我们将通过以下方式实现这一目标：1。完成鼠伤寒沙门氏菌所有非必需基因的缺失文库，2。在小鼠模型中筛选我们的完整缺失集合以鉴定参与系统性定植的新基因，3。证实每个突变体对于系统定殖是有缺陷的，4.表征在培养的巨噬细胞中结合、侵入和复制的能力方面有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140万例腹泻病，并且是美国主要在免疫功能低下人群中与病毒，寄生虫或细菌相关的食源性疾病死亡的最常见原因。在幼儿和HIV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，特别是在撒哈拉以南非洲的上升，导致与NTS相关的全身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全身性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.