Genome defense and acquired antibiotic resistance in Enterococcus faecalis and Enterococcus faecium

粪肠球菌和屎肠球菌的基因组防御和获得性抗生素耐药性

• 批准号: 9248244
• 负责人: KELLI LEA PALMER
• 金额: $ 38.25万
• 依托单位: UNIVERSITY OF TEXAS DALLAS
• 依托单位国家: 美国
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-04-15 至 2020-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9248244
• 关键词: Address; Alpha Cell; Antibiotic Resistance; Antibiotic Therapy; Antibiotics; Antitoxins; Award; Bacteria; Bacteriophages; Bioinformatics; Cell Wall; Cells; Characteristics; Clinical; Clustered Regularly Interspaced Short Palindromic Repeats; Development; Discrimination; Enterococcus; Enterococcus faecalis; Enterococcus faecium; Environment; Evolution; Genes; Genetic Materials; Genome; Heterogeneity; Hospitals; Human; In Vitro; Intestines; Link; Memory; Memory Loss; Mobile Genetic Elements; Modeling; Modification; Molecular; Multi-Drug Resistance; Mutagenesis; National Institute of Allergy and Infectious Disease; Nosocomial Infections; Orphan; Pheromone; Phylogenetic Analysis; Plasmids; Population; Public Health; Publishing; Reporting; Research; Structure; Symbiosis; System; Testing; Time; Toxin; United States; Virulence Factors; Work; acquired immunity; antimicrobial; biological adaptation to stress; deep sequencing; killings; pathogen; public health relevance; resistance factors; segregation

 DESCRIPTION (provided by applicant): Enterococcus faecalis and E. faecium are normal human intestinal tract colonizers and opportunistic pathogens that are among the leading causes of hospital-acquired infections in the US. Specific phylogenetic lineages of E. faecalis and E. faecium cause hospital-acquired infections. These hospital enterococci are multidrug-resistant and possess dramatically expanded genomes relative to commensal enterococcal strains. Genome expansion is due to the acquisition of mobile genetic elements (MGEs) such as plasmids and phage. Interestingly, hospital enterococci lack CRISPR-Cas systems. CRISPR-Cas are prokaryotic genome defense systems that serve as molecular memories of past MGE encounters and that provide acquired immunity against MGEs. These results suggest that antibiotic treatment inadvertently selects for enterococci with enhanced abilities to acquire MGEs. The central hypothesis guiding this research is that compromised genome defense combined with strong selection for MGEs leads to the emergence of multidrug-resistant, genome- expanded enterococci endemic to clinical environments. In preliminary work supported by a NIAID K22 Research Scholar Development Award, we demonstrated that a CRISPR-Cas system in commensal E. faecalis acts as an impediment to the acquisition of antibiotic resistance. The research in this proposal investigates the function of a unique orphan CRISPR locus occurring in hospital E. faecalis strains, called CRISPR2, which regulates the antimicrobial stress response of those strains (Aim 1). We have observed that acquisition of an antibiotic resistance plasmid by commensal E. faecalis leads to molecular memory loss (CRISPR deletion) in plasmid-containing cells over time. Mechanisms by which the plasmid evades host CRISPR-Cas defense and induces molecular memory loss will be investigated (Aim 2). Finally, we investigate the hypothesis that hospital enterococci are dysfunctional for `self' versus non-self recognition; i.e. genome modification defense (Aim 3).

 描述（由申请人提供）：粪肠球菌和屎肠球菌是正常的人类肠道定植菌和机会性病原体，是美国医院获得性感染的主要原因之一。粪肠球菌和屎肠球菌的特定系统发育谱系导致医院感染。 - 获得性感染。这些医院肠球菌具有多重耐药性，并且相对于共生肠球菌菌株具有显着扩展的基因组。提示，医院肠球菌缺乏 CRISPR-Cas 系统，以获取移动遗传元件 (MGE)。 CRISPR-Cas 是原核基因组防御系统，可作为过去 MGE 遭遇的分子记忆，并提供针对 MGE 的获得性免疫力。这些结果表明，抗生素治疗无意中选择了获得 MGE 能力增强的肠球菌。指导这项研究的中心假设是，基因组防御受损与对 MGE 的强烈选择相结合，导致了肠球菌的产生。在 NIAID K22 研究学者发展奖支持的初步工作中，我们证明了共生粪肠球菌中的 CRISPR-Cas 系统阻碍了临床环境中流行的多重耐药性、基因组扩增肠球菌的出现。该提案中的研究调查了医院粪肠球菌菌株中出现的独特孤儿 CRISPR 基因座（称为 CRISPR2）的功能，该基因座调节这些菌株的抗菌应激反应。我们观察到，随着时间的推移，共生粪肠球菌获得抗生素抗性质粒会导致含有质粒的细胞丧失分子记忆（CRISPR 缺失），并通过该机制逃避宿主的 CRISPR-Cas 防御。最后，我们研究了医院肠球菌对“自我”与非自我识别功能障碍的假设；基因组修饰防御（目标 3）。