Quelling UPEC Proliferation by Lactobacillus Mediated Induction of Latent Phages

先前的研究发现，几种乳杆菌能抑制或杀死细菌的生长。 尿路致病性大肠杆菌(UPEC)。Lactobacilluscrispatus、L.asseri、L.iners和L. Jensenii是健康女性阴道和尿路微生物区系中常见的优势成员 并与缺乏下尿路症状有关，包括尿路 感染(尿路感染)。尿液乳杆菌产生过氧化氢(H_2O_2)和乳酸，两者都 这会给UPEC细胞带来压力，并归因于减少了在膀胱内的定植。AS 噬菌体生物学家和第一个研究尿液生物群中噬菌体的小组，我们发现了一种 乳酸菌为主的环境与温带噬菌体的直接联系 归纳法。我们先前对尿路细菌(尿路生物群)的基因组调查发现，大多数 细菌基因组有潜在的(整合的)噬菌体基因组，我们先前的经验工作表明 这些潜伏噬菌体中的大多数实际上都是能够被诱导的温带噬菌体。这个 诱导噬菌体从细菌基因组中切除，复制，并裂解(杀死)其细菌宿主 手机。我们的概念验证工作发现：(I)无细胞乳杆菌上清液可以诱导UPEC 潜温性噬菌体(大肠杆菌)，(Ii)乳杆菌相关pH值的液体培养可以 诱导UPEC温带大肠杆菌噬菌体，以及(Iii)乳杆菌相关过氧化氢水平的液体培养 可诱导UPEC温带大肠菌群。这就引出了我们的假设：乳酸菌可能控制 UPEC的定植通过“从内裂解”--H_2O_2和/或pH胁迫UPEC菌株， 导致常驻温带大肠菌群的诱导和UPEC细胞的死亡。 采用跨学科方法，拟议的项目将评估频率和 乳杆菌诱导UPEC噬菌体产生的原因。目标1将扩大我们的前期工作 确定所有常见尿液乳杆菌的无细胞培养上清液是否诱导 UPEC噬菌体；将测试多个菌株的卷曲乳杆菌、加瑟氏乳杆菌、伊氏乳杆菌和简氏乳杆菌。 在从患有和不患有LUT的女性膀胱中分离出的大量大肠杆菌上， 包括UTI。在目标2中，我们将确定是否由无细胞乳杆菌触发的噬菌体诱导 上清液是由pH和/或过氧化氢水平引发的压力的结果。此外，我们还将 确定随着时间的推移，pH值和过氧化氢如何影响UPEC生长。我们的调查将决定 噬菌体诱导在塑造尿路生物群中起着重要作用。了解相关机制 控制UPEC定植可以为临床治疗急性尿路感染提供信息。 该项目被提议作为面向本科院校的R15领域，并且是 旨在让本科生参与良性泌尿系统疾病的跨学科研究。

Prior studies have found that several Lactobacillus species inhibit the growth of or kill uropathogenic Escherichia coli (UPEC). Lactobacillus crispatus, L. gasseri, L. iners, and L. jensenii are frequent dominant members of both the healthy female vaginal and urinary microbiota and have been associated with the lack of lower urinary tract symptoms, including urinary tract infections (UTIs). Urinary Lactobacilli produce hydrogen peroxide (H2O2) and lactic acid, both of which can stress the UPEC cell and are attributed to reduced colonization within the bladder. As phage biologists and the first group to investigate phages within the urobiome, we recognized an immediate connection between Lactobacillus-dominated environments and temperate phage induction. Our prior genomic survey of bacteria in the urinary tract (urobiome) found that most bacterial genomes have latent (integrated) phage genomes, and our prior empirical work suggests that most of these latent phages are in fact temperate phages capable of being induced. The induced phage excises from the bacterial genome, replicates, and lyses (kills) its bacterial host cell. Our proof-of-concept work found: (i) cell-free Lactobacillus supernatant can induce UPEC latent temperate phages (coliphages), (ii) liquid cultures at Lactobacillus-relevant pH values can induce UPEC temperate coliphages, and (iii) liquid cultures at Lactobacillus-relevant H2O2 levels can induce UPEC temperate coliphages. This leads to our hypothesis: Lactobacilli may control UPEC colonization via “lysis from within” – H2O2 and/or pH stress UPEC strains, which leads to induction of resident temperate coliphages and death of the UPEC cell. Taking an interdisciplinary approach, the proposed project will assess the frequency and cause of induction of UPEC coliphages by Lactobacillus. Aim 1 will expand our preliminary work to determine if the cell-free supernatant of all common urinary Lactobacillus species induces UPEC coliphages; multiple strains of L. crispatus, L. gasseri, L. iners, and L. jensenii will be tested on a large collection of E. coli isolated from the bladders of females with and without LUTS, including UTI. In Aim 2, we will ascertain if phage induction triggered by cell-free Lactobacillus supernatant is the result of stress triggered by pH and/or H2O2 levels. Additionally, we will determine how pH and H2O2 impact UPEC growth over time. Our investigation will determine what role phage induction plays in shaping the urobiome community. Understanding the mechanisms that control UPEC colonization can inform clinical care of acute UTIs. This project is proposed as an R15 AREA for Undergraduate-Focused Institutions and is designed to engage undergraduates in interdisciplinary research of benign urologic disease.