Molecular mechanisms of lytic bacteriophage infection of enterococci

肠球菌裂解性噬菌体感染的分子机制

• 批准号: 10309178
• 负责人: Cydney N Johnson
• 金额: $ 3.4万
• 依托单位: UNIVERSITY OF COLORADO DENVER
• 依托单位国家: 美国
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-08-01 至 2023-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10309178
• 关键词: Address; Adsorption; Alternative Therapies; Animals; Anti-Bacterial Agents; Antibiotic Resistance; Antibiotic Therapy; Antibiotics; Antigens; Bacteria; Bacterial Infections; Bacteriophages; Binding; Biochemical; Biological Assay; Biology; Blood Circulation; Cell Wall; Cell membrane; Cell surface; Cells; Cellular biology; Clinical; Cytolysis; DNA; DNA Restriction-Modification Enzymes; Data; Development; Enterobacteriaceae; Enterococcus; Enterococcus faecalis; Event; Genes; Genetic; Genome; Genomic DNA; Goals; Hospitals; Human; Individual; Infection; Intestines; Knowledge; Lactococcus; Lead; Life; Lytic; Modeling; Modification; Molecular; Multi-Drug Resistance; Mutation; Nosocomial Infections; Outcome; Phage Receptors; Pharmaceutical Preparations; Plasmids; Polysaccharides; Pseudomonas; Publishing; Receptor Gene; Resistance; Sepsis; Specificity; Streptococcus; System; Therapeutic; Treatment Efficacy; Vancomycin; Vancomycin Resistance; Viral; Virion; Virulence Factors; Virus; Work; bacterial fitness; base; candidate selection; combat; design; experimental study; fitness; genetic approach; insight; intestinal barrier; multi-drug resistant pathogen; novel; particle; pathogen; pathogenic bacteria; receptor; resistance factors; secondary infection; therapeutic candidate

PROJECT SUMMARY In recent decades there has been a rapid decline in effective antibiotic therapies and an increase in multidrug- resistant (MDR) bacterial infections. One common MDR pathogen is the Gram-positive intestinal bacterium Enterococcus faecalis which resists many antibiotics including “last-line-of-defense” drugs such as vancomycin. MDR enterococci can expand in the intestine in individuals undergoing broad-spectrum antibiotic therapy. This expansion can lead to E. faecalis translocation to the bloodstream, sepsis, and further shedding of the bacterium, thus perpetuating these hospital-acquired infections. One potential strategy to combat MDR enterococci is the use of bacteriophages (phages). Phages are viruses that infect and kill bacteria with high specificity. Phage infection relies on binding to the bacterial cell surface, ejection of phage DNA into the bacterial cell, replication of the phage genome, and viral particle release from the cell. The use of phages as therapeutics raises concern similar to antibiotic use; bacteria will become resistant to infection, diminishing therapeutic efficacy. Thus, before phages can become a standard clinical therapy, we must clearly understand the specific mechanisms used by phages to infect bacteria and how bacteria respond to phage infection. To begin to elucidate the mechanisms used by phages during infection, I challenged E. faecalis with lytic phages and found that the enterococcal polysaccharide antigen is used for initial phage adsorption to various E. faecalis strains, including strains that the phage cannot successfully infect. Along with this, I have shown that the presence of a mobile plasmid in E. faecalis restricts phage infection. The goals of this project are to fill key gaps in our basic knowledge of phage-bacteria interactions and to provide insights into the mechanisms that influence the outcomes of phage infection, which will be beneficial knowledge for applied phage therapies. This project encompasses the following two Specific Aims: Aim 1: Identify the receptor that promotes DNA entry of Epa-dependent phages. This will be addressed through complementary biochemical assays to identify the receptor that promotes phage DNA entry into E. faecalis. Aim 2: Define the genetic basis of endogenous plasmids in restricting enterococcal phage infection. Here, I will use genetic approaches to identify a novel, enterococcal anti-phage restriction mechanism encoded on a mobile plasmid. These experiments will reveal new insights into the mechanisms that dictate enterococcal phage recognition and infection that will ultimately aid in the development of informed phage therapies. In doing so, my results will expand our basic knowledge surrounding enterococcal cell biology during phage infection and potentially identify new targets for anti-enterococcal therapies.

项目摘要 近几十年来，有效的抗生素疗法迅速下降，多药的增加 抗性（MDR）细菌感染。一种常见的MDR病原体是革兰氏阳性肠道细菌 抗肠球菌的肠球菌抵抗了许多抗生素，包括“防御性”药物，例如 万古霉素。 MDR肠球菌可以在接受广谱抗生素的个体中扩展肠道 治疗。这种膨胀会导致大肠杆菌易位到血液，败血症和进一步的脱落 打击MDR的一种潜在策略 肠球菌是细菌（噬菌体）的使用。噬菌体是感染并杀死高细菌的病毒 特异性。噬菌体感染依赖于与细菌细胞表面的结合，噬菌体DNA射入 细菌细胞，噬菌体基因组的复制以及从细胞释放的病毒颗粒。使用噬菌体作为 治疗学引起了类似于使用抗生素的关注；细菌将抗感染，减少 治疗效率。在噬菌体成为标准的临床疗法之前，我们必须清楚地了解 噬菌体用来感染细菌的特定机制以及细菌对噬菌体感染的反应。到 我开始阐明感染过程中噬菌体使用的机制，我对粪肠球菌提出了质疑 并发现肠球菌多糖抗原用于初始噬菌体吸附到各种E。 粪便菌株，包括噬菌体无法成功感染的菌株。除此之外，我已经证明了 粪肠球菌中移动质粒的存在限制了噬菌体感染。该项目的目标是填写密钥 在我们对噬菌体 - 细菌相互作用的基本知识中的差距，并提供对机制的见解 影响噬菌体感染的结果，这将是应用噬菌体疗法的有益知识。这 项目涵盖以下两个具体目标：目标1：确定促进DNA进入的接收器 依赖EPA的噬菌体。这将通过互补的生化分析来解决 促进噬菌体DNA进入大肠杆菌的受体。目标2：定义内源性的遗传基础 在限制肠球菌噬菌体感染的质粒。在这里，我将使用遗传方法来识别 在移动质粒上编码的新型肠球菌抗流量限制机制。这些实验会 揭示有关决定肠球噬菌体识别和感染的机制的新见解 最终有助于开发知情的噬菌体疗法。这样，我的结果将扩大我们的基本 噬菌体感染期间围绕肠肠细胞生物学的知识，并有可能确定 抗肠球菌疗法。