Mechanisms of anti-phage defenses and their mobilization in staphylococci

项目摘要 葡萄球菌是人类皮肤上普遍存在的细菌居民，是导致皮肤耐药性的主要原因。 感染.在约40种皮肤伴生种中，S.金黄色葡萄球菌和表皮的致病性最强 潜势：S.金黄色葡萄球菌是皮肤和软组织感染的主要原因，表皮是最常见的 与留置医疗器械相关的感染原因。问题是，S。表皮菌株 具有增强适应性/毒性的基因库（例如编码毒素和抗生素的基因 电阻），其可以水平地转移到S。金黄色。根据这些事实， 这些物种之间基因水平转移的调控机制将是一笔宝贵的财富 在源头上消除或阻止这些因素的流动。在这种情况下，葡萄球菌（即， 病毒）和针对它们的免疫系统对葡萄球菌的存活有深远的影响， 发病机制例如，溶原性大肠杆菌可以通过转移致病性来增强致病潜力 岛从一个菌株到另一个菌株，并携带毒力因子，与噬菌体基因组整合到 主持人相比之下，严格的裂解酶可以在几分钟内杀死细菌宿主，并被用作 对抗抗药性感染的替代疗法。细菌免疫系统靶向裂解和 溶原性的类似，因此可以对抗这些相反的作用。就目前情况而言， 了解这些动态并识别葡萄球菌所使用的特定免疫系统， 令人担忧的是，人们对这些系统如何横向分布几乎一无所知。这些知识空白 继续破坏我们实施有效治疗和改善整体医疗结果的能力。 该R 01项目的长期目标是全面了解抗噬菌体免疫 葡萄球菌中的系统及其传播途径。为此，本研究采用S。 epidermidis和一系列不同的表皮细胞作为模式生物，以实现三个具体目标：目标1将 在一组S.表皮病临床分离株的遗传学研究， 生物化学和生物信息学方法。目标2将确定主要的遗传和环境因素 利用分子和遗传学方法来驱动这些防御的动员。目标3旨在确定 使用高通量遗传学介导防御动员的分子机制的全球影响 接近。通过揭示葡萄球菌中抗噬菌体防御机制的新见解， 这些疾病传播的途径，拟议的工作将有助于开发更有效的方法 不仅可以对抗抗生素耐药性的传播， 类似的命运。这项工作也将在了解葡萄球菌方面开辟令人兴奋的新研究方向 以及其他拥有类似系统的生物。

Project Summary Staphylococci are ubiquitous bacterial residents of human skin and major causes of antibiotic-resistant infections. Of the ~40 skin-associated species, S. aureus and S. epidermidis have the greatest pathogenic potential: S. aureus is the leading cause of skin and soft tissue infections and S. epidermidis is the most common cause of infections associated with indwelling medical devices. Compounding the problem, S. epidermidis strains harbor a reservoir of genes that enhance fitness/virulence (e.g. genes that encode toxins and antibiotic resistance) which can be horizontally transferred to S. aureus. In light of these facts, a thorough understanding of the mechanisms that regulate horizontal gene transfer between these species would be an invaluable asset in neutralizing or stemming the flow of these factors at the source. In this context, staphylococcal phages (i.e. viruses) and the immune systems targeted against them have profound impacts on staphylococcal survival and pathogenesis. For instance, lysogenic phages can enhance pathogenic potential by transferring pathogenicity islands from one strain to another and carrying virulence factors that integrate along with the phage genome into the host. In contrast, strictly lytic phages can kill the bacterial host within minutes and are being used as alternative therapeutics to combat antibiotic-resistant infections. Bacterial immune systems target lytic and lysogenic phages alike, and can therefore counter these opposing effects. As it stands, we are only just beginning to understand these dynamics and identify the specific immune systems that staphylococci employ, and alarmingly, almost nothing is known about how these systems are horizontally spread. These knowledge gaps continue to undermine our ability to implement effective therapeutics and improve overall healthcare outcomes. The long-term objective of this R01 project is to gain a comprehensive understanding of the anti-phage immune systems in staphylococci and the pathways by which they spread. Towards this goal, this research uses S. epidermidis and a collection of diverse phages as model organisms to achieve three specific aims: Aim 1 will identify and characterize new anti-phage defenses in a suite of S. epidermidis clinical isolates using genetics, biochemical, and bioinformatics approaches. Aim 2 will determine the major genetic and environmental factors that drive mobilization of these defenses using molecular and genetic approaches. Aim 3 seeks to determine the global impacts of the molecular machinery that mediate defense mobilization using high-throughput genetics approaches. By revealing new insights into mechanisms of anti-phage defenses in staphylococci and the pathways by which they spread, the proposed work will enable the development of more effective approaches for not only combatting the spread of resistance to antibiotics but also saving the burgeoning phage therapeutics from a similar fate. This work will also open up exciting new research directions in understanding staphylococci and other organisms that harbor similar systems.