A safe, targeted, designer probiotic to prevent or treat C. difficile infection

 描述(由申请人提供)：本提案的总体目标是设计(R21)和评估(R33)下一代新型益生菌，旨在预防或治疗腹泻病原体艰难梭菌的感染，从而限制对抗生素治疗的依赖。为R21阶段提出了三个具体目标。在目标1中，我们将在我们现有的第一代益生菌中通过基因工程实现完全的生物遏制，这样除非继续服用，否则它将在3-5天内从胃肠道中消失。此外，它的抗C.艰难梭菌感染(CDI)特性仅在伴随的糖替代补充时表现出来。在目标2中，我们将评估第二代益生菌的体外性质。在目标3中，我们将确定定植效力，并进行概念验证抗CDI效力研究。将提供可量化的过渡里程碑，以便进展到R33阶段，在该阶段提出了两个具体目标。在目标4中，我们将确定剂量、递送和生物遏制效果。在目标5中，我们将综合评价生物治疗剂预防或治疗CDI(包括初次感染和复发)的能力，诱导对特定抗原的适应性免疫反应(S)，以及在抗生素抑制或CDI特异性生物失调后影响内源微生物区系恢复的能力。因此，这项工作的直接影响将是通过对其疾病预防方式的全面询问来验证我们的代理人的临床前准备情况。

 DESCRIPTION (provided by applicant): The overall goal of this proposal is to engineer (R21) and evaluate (R33) the next generation of a novel probiotic designed to prevent or treat infection by the diarrheagenic pathogen Clostridium difficile and, thereby, limit reliance on antibiotic therapy. Three Specific Aims are proposed for the R21 phase. In Aim 1, we will genetically engineer complete bio-containment into our existing first-generation probiotic, so that it will be lost from the gastrointestinal tract over 3-5 days unless continually dosed. Further, its anti-C. difficile infection (CDI) property will be expressed only upon concomitant sugar-substitute supplementation. In Aim 2, we will assess in vitro properties of the second-generation probiotic. In Aim 3, we will determine colonization efficacy, and also perform proof-of-concept anti-CDI efficacy studies. Quantifiable transition milestones will be available in order to progress to the R33 phase, where two Specific Aims are proposed. In Aim 4, we will determine dosing, delivery and biological containment efficacy. In Aim 5, we will comprehensively evaluate ability of the biotherapeutic agent to prevent or treat CDI (including primary infection and relapse), elicit adaptive immune response(s) to specific antigens, and impact endogenous microbiota recovery following antibiotic suppression or CDI-specific dysbiosis. Thus, the immediate impact of this work will be to verify pre-clinical readiness of our agent, via comprehensive interrogation of its disease-preventing modalities.