EBPA-FIBROGEN INTERACTION IN ENTEROCOCCUS FAECALIS CAUTI

描述（由申请人提供）：导尿管相关性尿路感染（CAUTIs）是最常见的医院感染之一，如果不治疗可导致严重的并发症，包括菌血症和死亡。粪肠球菌（Enterococcus faecalis）是CAUTI的主要病原体，其在宿主体内的粘附和持续存在能力以及多种抗生素耐药性使其难以预防和治疗。此外，尽管在CAUTI期间存在强烈的炎症反应，粪肠球菌仍能形成生物膜并生长。粪肠球菌如何附着、在膀胱中生长、形成生物膜的分子细节以及生物膜在CAUTI中持久性的重要性尚不清楚。该项目将使用最近优化的粪肠球菌CAUTI模型来了解粪肠球菌Epb毛菌和纤维蛋白原之间的相互作用如何导致疾病。需要解决的重要问题包括菌毛的EbpA亚基如何与纤维蛋白原结合的分子分析以及这种相互作用对CAUTI的重要性。在体外生物膜形成缺陷的突变体完全有能力形成

DESCRIPTION (provided by applicant): Catheter-associated urinary tract infections (CAUTIs) are one of the most common nosocomial infections and if untreated can lead to serious complications including bacteremia and death. Enterococcus faecalis is a leading causative agent of CAUTI and its ability to adhere and persist within the host along with its multiple antibiotic resistances makes it difficult to prevent and treat. Furthermore, E. faecalis can form biofilm and grow despite a robust inflammatory response during CAUTI. The molecular details of how E. faecalis adheres, grows in the bladder, forms biofilm and the importance of biofilm in persistence in CAUTI are not well understood. This project will use a recently optimized model of E. faecalis CAUTI to understand how interactions between the E. faecalis Epb pilus and fibrinogen contribute to disease. Important questions to be addressed include a molecular analysis of how the EbpA subunit of the pilus binds to fibrinogen and the importance of this interaction to CAUTI. Mutants defective for biofilm formation in vitro are fully capable of forming biofilm in murine CAUTI, suggesting that standard biofilm models do not reproduce relevant in vivo conditions. This project will evaluate a new model of fibrinogen-supplemented urine biofilms to determine if genes required for biofilm in this model are also required for biofilm in murine CAUTI and will test the importance of biofilm in causing disease. Finally, we have data to suggest that an EbpA subunit-based vaccine protects against murine CAUTI and that immunized animals generate antibody that blocks EbpA-fibrinogen binding. The project will test the protective efficacy of various EbpA sub-domain and peptide vaccines in comparison to formulations that use other pilus sub- units. Combined with passive transfers of sera from immunized animals and characterization of antibody responses, it will be possible to specifically test whether the mechanism of protection depends on blocking EbpA-fibrinogen binding. The data generated by this project will provide significant new insights into the pathogenesis of CAUTI with direct application to the development of new modalities of therapy. .