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，有效的抗生素治疗迅速减少，多药治疗增加， 耐药（MDR）细菌感染。一种常见的MDR病原体是革兰氏阳性肠道细菌 粪肠球菌耐许多抗生素，包括“最后一道防线”的药物， 万古霉素耐多药肠球菌可在接受广谱抗生素治疗的个体中在肠道内扩张 疗法这种膨胀可以导致E.粪便移位到血液中，脓毒症和进一步脱落 细菌，从而延续这些医院获得性感染。对抗MDR的一种潜在策略 肠球菌是使用噬菌体（噬菌体）。噬菌体是感染并杀死细菌的病毒， 的特异性噬菌体感染依赖于与细菌细胞表面的结合，将噬菌体DNA喷射到细菌细胞表面。 细菌细胞、噬菌体基因组的复制和病毒颗粒从细胞中释放。使用EQUIPAS 治疗引起了类似抗生素使用的关注;细菌将对感染产生抗药性， 疗效因此，在骨水泥成为标准的临床治疗方法之前，我们必须清楚地认识到， 噬菌体感染细菌的具体机制以及细菌对噬菌体感染的反应。到 开始阐明Escherichia coli在感染过程中使用的机制，我挑战了E.溶菌性粪炎 并发现肠球菌多糖抗原用于对各种大肠杆菌的初始噬菌体吸附。 粪杆菌菌株，包括噬菌体不能成功感染的菌株。与此沿着，我还表明， 大肠杆菌中存在移动的质粒。粪便限制噬菌体感染。该项目的目标是填补关键 我们在噬菌体-细菌相互作用的基础知识的差距，并提供深入了解的机制， 影响噬菌体感染的结果，这将是有益的知识，应用噬菌体治疗。这 该项目包括以下两个具体目标：目标1：识别促进DNA进入的受体 依赖EPA的人。这将通过补充的生物化学测定来解决，以确定 一种促进噬菌体DNA进入E.粪便。目的2：确定内源性的遗传基础 质粒限制肠球菌噬菌体感染。在这里，我将使用遗传方法来识别一个 在移动的质粒上编码的新的肠球菌抗噬菌体限制性机制。这些实验将 揭示了决定肠球菌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。这样做，我的结果将扩大我们的基本 了解噬菌体感染期间肠球菌细胞生物学，并可能确定新的靶点， 抗肠球菌疗法。