CRISPR defense and acquired antibiotic resistance in Enterococcus faecalis

描述(申请人提供)：肠球菌是一种机会致病菌，可在人类中引起危及生命的感染。我的研究的一个主要目标是表征有助于肠球菌中抗生素耐药性演变的机制。拟议的研究将集中在粪肠球菌上，自20世纪80年代以来，由于与医院获得性感染和多重耐药有关，包括对最后一线抗生素万古霉素的耐药性，粪肠球菌越来越臭名昭著。粪肠球菌的某些系统发育谱系与通过水平基因转移和医院地方性获得的抗生素耐药性有关--这些是高风险或医院适应的谱系。这项拟议的研究涉及最近发现的可能的原核生物免疫系统，集群，规则间隔的短回文重复序列(CRISPR)-CA，与多药耐药粪肠球菌的出现和持续存在的关系。CRISPR-Cas防御系统的丧失可能通过获得新的特征，如抗生素耐药性，促进持续I期临床环境，从而促进高危肠球菌谱系的进化和扩展。本研究的具体目的是：1)验证CRISPR-Cas干扰粪肠球菌获得质粒的假说，2)表征小CRISPR RNA加工的要求，3)通过CRISPR分型分析粪肠球菌的种群结构。这项研究将为粪肠球菌的抗生素耐药性和毒力基因增加提供潜在的机制，并对鉴定具有重要意义。 可安全用于工业用途的粪肠球菌菌株。粪肠球菌是美国医疗保健相关感染的主要原因之一。通过水平基因转移获得的多药耐药性是粪肠球菌高危菌株的特点。这项拟议的研究将评估可能的原核免疫系统CRISPR-Cas在控制粪肠球菌水平基因转移中的作用。

DESCRIPTION (provided by applicant): Enterococci are opportunistic pathogens that cause life-threatening infections in humans. An overarching goal of my research is to characterize mechanisms contributing to the evolution of antibiotic resistance in the enterococci. The proposed research will focus on Enterococcus faecalis, which since the 1980s has gained increasing notoriety from association with hospital-acquired infections and multidrug resistance including resistance to the last-line antibiotic vancomycin. Certain phylogenetic lineages of E. faecalis are associated with antibiotic resistance acquired through horizontal gene transfer and hospital endemicity - these are the high-risk, or hospital-adapted, lineages. The proposed research concerns the relationship of the recently discovered putative prokaryotic immune system, Clustered, Regularly Interspaced Short Palindromic Repeats (CRISPR)-Cas, with the emergence and continuing persistence of multidrug resistant E. faecalis. Loss of CRISPR-Cas defense may have contributed to the evolution and expansion of high-risk enterococcal lineages by enabling acquisition of new traits, such as antibiotic resistance, that facilitate persistence i clinical environments. The specific aims of this research are to: 1) test the hypothesis that CRISPR-Cas interferes with plasmid acquisition by E. faecalis, 2) characterize requirements for small CRISPR RNA processing, and 3) analyze E. faecalis population structure by CRISPR typing. This research will provide insight into a potential mechanism contributing to antibiotic resistance and virulence gene accretion in E. faecalis, and has implications for the identification of E. faecalis strains safe for industrial use. The bacterium Enterococcus faecalis is among the leading causes of healthcare-associated infections in the United States. Multidrug resistance acquired by horizontal gene transfer is characteristic of high-risk E. faecalis strains. The proposed research will evaluate the role of the putative prokaryotic immune system CRISPR-Cas in control of horizontal gene transfer in E. faecalis.