Bacteriophage-based probiotic preparations and their effect on the gut microflora

描述（由申请人提供）：人类胃肠道（GI）定植有丰富多样的微生物群。许多因素（例如，抗生素治疗、饮食等）可能改变肠道正常和有益的细菌植物群，这可能导致各种慢性和退行性疾病，这些疾病在幼儿和老年人中尤其成问题。用于缓解这些病症的方法之一是摄入益生菌;即，各种非致病性细菌（例如，乳酸杆菌和双歧杆菌），当摄入足够量时可以改善健康。然而，尚未受到太多关注的潜在有用的益生菌干预是使用噬菌体靶向人胃肠道中的“问题”细菌物种。噬菌体（或噬菌体）是感染细菌的病毒。它们是地球上最丰富的微生物，在维持众多生态系统中平衡的细菌种群方面发挥着关键作用。溶菌肽具有显著的抗菌活性;然而，与抗生素相反，它们是非常特异的;即，它们只裂解目标细菌种类的菌株。本申请中提出的研究解决了我们的假设，即由于其高特异性，噬菌体可用于有利地操纵哺乳动物肠道的微生物群落（通过靶向胃肠道中的特定“问题”细菌病原体），并且基于噬菌体的益生菌对肠道的有益微生物群落没有有害影响。我们将开始用L来评估我们的假设。单核细胞增生李斯特菌和单核细胞增生李斯特菌特异性噬菌体制备物（LMP-102）作为模型系统。我们建议，使单核细胞增生李斯特菌特异性噬菌体制剂的一部分，日常饮食可能会显着降低摄入的李斯特菌的风险。单核细胞增多症定植在胃肠道中并增殖到足够的水平以穿过肠粘膜并通过肠系膜淋巴结和血流传播。将解决以下三个具体目标：SA #1：开发遗传工具，以识别和监测单个单核细胞组分的L。SA#2：测定LMP-102单核细胞生成素-噬菌体制备物（LMP-102）在小鼠胃肠道中的持久性（在存在和不存在靶向的LMP-102噬菌体的情况下）。单核细胞增多症菌株），并测定其对L. SA#3：比较LMP-102和氨苄青霉素对健康小鼠和实验性感染单核细胞增多性李斯特菌的小鼠的肠道微生物群落的体内作用。本申请中的研究被设计为产生关于胃肠道中噬菌体-细菌相互作用的关键初步数据，并且它们可以导致开发用于预防和/或治疗由各种细菌病原体引起的疾病的新型益生菌制剂，所述细菌病原体具有口腔入口并且需要在胃肠道中短期或长期定殖以引起疾病。

DESCRIPTION (provided by applicant): The human gastrointestinal (Gl) tract is colonized by an abundant and diverse microbiota. Numerous factors (e.g., antibiotic treatment, diet, etc.) may alter the normal and beneficial bacterial flora of the gut, which may lead to various chronic and degenerative diseases that are particularly problematic in young children and the elderly. One of the approaches used to alleviate those disorders is the ingestion of probiotic bacteria; i.e., various nonpathogenic bacteria (e.g., lactobacilli and bifidobacteria) that may improve health when ingested in sufficient quantities. However, a potentially useful probiotic intervention that has not received much attention is to use bacteriophages to target "problem" bacterial species in the human Gl tract. Bacteriophages (or phages) are viruses that infect bacteria. They are the most abundant microorganisms on earth, and they play a key role in maintaining balanced bacterial populations in numerous ecosystems. Lytic phages have remarkable antibacterial activity; however, in contrast to antibiotics, they are very specific; i.e., they only lyse strains of their targeted bacterial species. The studies proposed in this application address our hypothesis that, because of their high specificity, bacteriophages may be useful in favorably manipulating the microflora of the mammalian intestinal tract (by targeting specific "problem" bacterial pathogens in the Gl tract), and that phage-based probiotics will have no deleterious effect on the beneficial microflora of the gut. We will begin to evaluate our hypothesis by using L. monocytogens and a L monocytogenes-specific phage preparation (LMP-102) as a model system. We propose that making a L monocytogenes-specific phage preparation part of a routine diet may significantly reduce the risk of ingested L. monocytogenes colonizing the Gl tract and proliferating to sufficient levels to cross the intestinal mucosa and disseminate via the mesenteric lymph nodes and bloodstream. The following three specific aims will be addressed: SA #1: Develop genetic tools to identify and monitor individual monophage components of L. monocytogenes-spectflc phage preparation (LMP-102) in vitro and in vivo; SA #2: Determine the persistence of LMP-102 monophages in the Gl tract of mice (in the presence and absence of the targeted L. monocytogenes strain) and determine their effect on L. monocytogenes colonization in experimentally-infected mice; SA #3: Compare the in vivo effects of LMP-102 and ampicillin on the intestinal microflora of healthy mice and mice experimentally-infected with L monocytogenes. The studies in this application are designed to yield critical preliminary data concerning bacteriophage-bacterial interactions in the Gl tract, and they may lead to the development of novel probiotic preparations for the prophylaxis and/or treatment of illnesses caused by various bacterial pathogens that have an oral portal of entry and require short- or long-term colonization in the Gl tract in order to cause disease.