Genetics of Salmonella Resistance to the Inflammatory Response in the Gut

沙门氏菌对肠道炎症反应的耐药性遗传学

• 批准号: 7712254
• 负责人: HELENE L ANDREWS-POLYMENIS
• 金额: $ 24.21万
• 依托单位: TEXAS A&M UNIVERSITY HEALTH SCIENCE CTR
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-08-11 至 2011-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7712254
• 关键词: Animal Model; Animals; Antimicrobial Resistance; Bacteria; Bacterial Genes; Candidate Disease Gene; Cattle; Cause of Death; Cells; Cistrons; Clinical; Collection; Complement; Defect; Defensins; Development; Diarrhea; Disadvantaged; Disease; Enteral; Environment; Epithelial; Epithelial Cells; Event; Exhibits; Face; Flushing; Foundations; Future; Gastroenteritis; Gastrointestinal tract structure; Gene Deletion; Genes; Genetic; Genetic Screening; Goals; Hour; Human; Immune response; Immunocompromised Host; In Vitro; Individual; Infection; Infiltration; Inflammation; Inflammatory; Inflammatory Response; Inflammatory disease of the intestine; Intestines; Leukocyte L1 Antigen Complex; Libraries; Livestock; Methods; Modeling; Molecular; Mucous Membrane; Organism; Parasites; Pathology; Persons; Process; Production; Proteins; Public Health; Relative (related person); Resistance; Salmonella; Salmonella enterica; Salmonella infections; Screening procedure; Serotyping; Staging; Study models; Symptoms; System; Texas; Therapeutic Intervention; United States; Universities; Virus; Work; antimicrobial; base; deletion library; experience; foodborne; foodborne illness; human disease; intestinal epithelium; killings; lambda Spi-1; mutant; neutrophil; new technology; novel; pathogen; public health relevance; response; transmission process

DESCRIPTION (provided by applicant): Non-typhoidal Salmonella, including serotype Typhimurium (STm) are food-borne bacterial pathogens that cause ~1.4 million cases of diarrheal disease annually in the United States and hundreds of millions of cases worldwide. In the intestine, STm induces a strong neutrophilic inflammatory response and the production of antimicobial compounds by intestinal epithelial cells. In the face of this inflammatory response the numbers of STm in the intestine increase sharply, while the intestinal microflora of the host are dramatically reduced. The objective of this proposal is to identify the bacterial factors that allow STm to resist being killed by antimicrobials produced by the intestinal epithelium. The calf is the natural model of diarrheal STm infection that is most similar to human disease in clinical signs, host responses, and intestinal pathology. We have developed a forward genetic system to make screening for mutants feasible in ligated ileal loops in calves, a model developed at Texas A&M. We have generated a collection of over 1000 targeted deletion strains in STm, including mutants in all "Salmonella-specific" genes and we have developed microarray-based methods to screen this entire collection of mutants as a single pool. We have already confirmed the use of this system for forward genetic screening in animal infection. In AIM-1 we will screen the mutant pool in calf ligated ileal loops to identify mutants sensitive to intestinal epithelial cell-derived antimicrobials. In AIM-2 we will verify and complement these mutants in competitive infections in ligated ileal loops in calves. In AIM-3 we will determine which of these genes are important for resistance to the purified antimicrobials calprotectin and enteric 2-defensin, antimicrobials known to be produced by the intestinal epithelium during inflammation. This project is a first step toward a comprehensive determination of the molecular mechanism of the bacterial genes involved in the response to inflammation in the gut. 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. The genes and mechanisms used by non-typhoidal Salmonellae to survive in the face of a host inflammatory response in the intestine are not well understood. These mechanisms allow Salmonellae to establish a niche in the intestine during infection, and they are shed from this niche in fecal material from infected persons and livestock continuing the cycle of transmission. Development of a better understanding of the genes and mechanisms involved in this important stage of infection is critical to breaking the cycle of transmission of this organism. This work will have a direct impact on public health.

描述（由申请人提供）：非伤寒沙门氏菌，包括血清型鼠伤寒 (STm) 是食源性细菌病原体，每年在美国引起约 140 万例腹泻病，在全世界引起数亿例腹泻病。在肠道中，STm 诱导强烈的中性粒细胞炎症反应，并由肠上皮细胞产生抗菌化合物。面对这种炎症反应，肠道中 STm 的数量急剧增加，而宿主肠道菌群却急剧减少。该提案的目的是确定使 STm 能够抵抗肠上皮产生的抗菌剂杀死的细菌因素。 小牛是腹泻性 STm 感染的自然模型，其临床症状、宿主反应和肠道病理与人类疾病最相似。我们开发了一种正向遗传系统，可以在小牛的结扎回肠环中筛选突变体，这是德克萨斯农工大学开发的一个模型。我们已经在 STm 中生成了超过 1000 个靶向缺失菌株的集合，包括所有“沙门氏菌特异性”基因中的突变体，并且我们开发了基于微阵列的方法，以将整个突变体集合作为单个库进行筛选。我们已经确认该系统可用于动物感染的正向遗传筛查。 在 AIM-1 中，我们将筛选小牛结扎回肠环中的突变体池，以鉴定对肠上皮细胞衍生的抗菌剂敏感的突变体。 在 AIM-2 中，我们将在小牛结扎回肠环的竞争性感染中验证和补充这些突变体。 在 AIM-3 中，我们将确定哪些基因对于纯化抗菌剂钙卫蛋白和肠 2-防御素（已知在炎症过程中由肠上皮产生的抗菌剂）的耐药性非常重要。 该项目是全面确定参与肠道炎症反应的细菌基因分子机制的第一步。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，主要是免疫功能低下的人群。非伤寒沙门氏菌在肠道宿主炎症反应中生存的基因和机制尚不清楚。这些机制使沙门氏菌在感染期间在肠道中建立一个生态位，并从感染者和牲畜的粪便中从这个生态位中排出，继续传播循环。更好地了解感染这一重要阶段所涉及的基因和机制对于打破这种生物体的传播周期至关重要。这项工作将对公众健康产生直接影响。