Gastrointestinal Colonization of Diarrheagenic Clostridium difficile

腹泻性艰难梭菌的胃肠道定植

• 批准号: 8142509
• 负责人: Gayatri Vedantam
• 金额: --
• 依托单位: SOUTHERN ARIZONA VA HEALTH CARE SYSTEM
• 依托单位国家: 美国
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-04-01 至 2015-09-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8142509
• 关键词: Acute; Address; Adherence; Adhesions; Affect; Age; Animal Model; Animals; Antibiotics; Arizona; Award; Bacteria; Bacterial Adhesins; Bacterial Adhesion; Binding; Biological Assay; Biology; Bioluminescence; Cells; Clostridium difficile; Data; Dependence; Disease; Dissection; Engineering; Epidemic; Epithelial Cells; Epithelium; Exclusion; Extracellular Matrix; Gene Expression Profile; Genes; Genetic; Goals; Hamsters; Health; Healthcare Systems; Hospitalization; Hospitals; Human; Image; Immune response; In Vitro; Infection; Intervention; Intestines; Kinetics; Knock-out; Lactobacillus acidophilus; Life; Ligands; Maps; Mass Spectrum Analysis; Mediating; Methodology; Minor; Molecular; Mus; Mutagenesis; Natural Immunity; Nature; Outcome; Patients; Peptides; Philosophy; Preventive Intervention; Principal Investigator; Probiotics; Process; Production; Proteins; Recurrence; Regulatory Element; Regulon; Relapse; Reproduction spores; Research; Resistance; Risk; Risk Factors; Role; Severities; Surface; Techniques; Technology; Testing; Therapeutic; Time; Translating; Translational Research; Veterans; Virulence; Virulent; Work; antimicrobial peptide; base; bench to bedside; capsule; clinically relevant; cost effective; factor C; gastrointestinal; genetic manipulation; in vitro Assay; in vivo; inhibitor/antagonist; lactic acid bacteria; microbiome; mouse model; mutant; prevent; programs; quorum sensing; surveillance study

DESCRIPTION (provided by applicant): Our current Merit Award focuses on factors contributing to virulence in Clostridium difficile, and a number of surface-layer proteins (SLPs) have been identified, that mediate bacterial adhesion to host intestinal epithelial cells. We now propose to significantly expand on these studies with the ultimate goal of translating our findings to a safe, easily utilizable, probiotic-based intervention for prevention of C. difficile infection (CDI). Three Specific Aims are proposed. First, we will define mechanistic bases of CD adherence to host epithelia mediated by surface-layer proteins (SLPs). CD mutagenesis and animal models of CDI will be exploited for these studies. Second, we will characterize non-SLP factors involved in CD colonization. Both bacterial and host- response proteins involved in, and contributing to, CD colonization as well as colonization resistance will be studied. Third, we will translate our bench-research findings to a clinically relevant outcome by developing a new adherence-based CDI intervention. This will involve construction of a targeted CD colonization inhibitor, by engineering a probiotic bacterium (Lactobacillus acidophilus) to express the CD colonization protein SlpA. We will validate the probiotic developed above by testing it against frequently isolated single-episode and relapse strains of CD recovered from surveillance studies performed at our VA hospital. For all studies in this proposal, we will use both the hamster and mouse models of acute CDI and CD colonization. We will also incorporate state-of-the-art methodologies including automated mass spectrometry and live-animal bioluminescence imaging to track the fate of ingested CD spores. PUBLIC HEALTH RELEVANCE: Over 400,000 cases of Clostridium difficile infection (CDI) occur annually in the USA, imposing a burden of >$3 billion on the healthcare system. Risk factors for CDI include hospitalization, age >65, co-morbid conditions, and antibiotic/PPI use - all of which are immediately relevant to patients treated in VA hospitals. Upto 11% of veterans also relapse with multiple recurrences of the disease. Severity of initial infection as well as relapses are also much higher with the newly emerged "hypervirulent" strains of C. difficile that are now common in VA hospitals. The studies proposed in this application are focused on understanding how C. difficile colonizes the human gut, and to validate a safe, cost-effective, easily tolerated intervention to prevent this establishment. The proposed work is thus consistent with the Merit Review mechanism, and is directly relevant to Veterans health.

描述（由申请人提供）： 我们当前的优异奖重点关注导致艰难梭状芽胞杆菌毒力的因素，并且已经鉴定出许多表面层蛋白（SLP），它们介导细菌粘附到宿主肠上皮细胞。我们现在建议大幅扩展这些研究，最终目标是将我们的研究结果转化为安全、易于利用、基于益生菌的干预措施，以预防艰难梭菌感染 (CDI)。提出了三个具体目标。首先，我们将定义表面层蛋白 (SLP) 介导的 CD 粘附到宿主上皮细胞的机制基础。这些研究将利用 CD 诱变和 CDI 动物模型。其次，我们将描述 CD 定植中涉及的非 SLP 因素。将研究参与并促进 CD 定植以及定植抗性的细菌和宿主反应蛋白。第三，我们将通过开发一种新的基于依从性的 CDI 干预措施，将我们的实验室研究结果转化为临床相关结果。这将涉及通过改造益生菌（嗜酸乳杆菌）来表达 CD 定植蛋白 SlpA，构建靶向 CD 定植抑制剂。我们将通过对从我们退伍军人管理局医院进行的监测研究中回收的经常分离的单次和复发 CD 菌株进行测试来验证上述开发的益生菌。对于本提案中的所有研究，我们将使用急性 CDI 和 CD 定植的仓鼠和小鼠模型。我们还将采用最先进的方法，包括自动质谱分析和活体动物生物发光成像来追踪摄入的 CD 孢子的命运。 公共卫生相关性： 美国每年发生超过 40 万例艰难梭菌感染 (CDI) 病例，给医疗保健系统带来超过 30 亿美元的负担。 CDI 的危险因素包括住院、年龄 >65 岁、合并症和抗生素/PPI 使用 - 所有这些都与在 VA 医院接受治疗的患者直接相关。高达 11% 的退伍军人也会出现病情多次复发的情况。由于目前在退伍军人管理局医院中常见的新出现的“高毒力”艰难梭菌菌株，初次感染和复发的严重程度也更高。本申请中提出的研究重点是了解艰难梭菌如何在人类肠道中定殖，并验证一种安全、经济有效、易于耐受的干预措施来防止这种情况的发生。因此，拟议的工作符合绩效审查机制，并且与退伍军人的健康直接相关。