Intra-species regulatory functions of fsr

描述(申请人提供)：粪肠球菌是引起心内膜炎、院内菌血症和尿路感染的主要原因。造成肠球菌感染治疗困难的两个特点是(1)对β-内酰胺类抗生素的耐受性和(2)引起生物被膜相关感染的倾向。β-内酰胺耐受性和生物被膜形成的调控仍未完全明确。这项研究事业奖的申请者萨蒂什·K·皮莱博士建议粪肠球菌群体感应基因座FSR基于其与金黄色葡萄球菌调节器AGR的同源性，也作为全球调节器发挥作用。利用AGR范式，FSR代表了粪肠球菌调节诸如抗生素耐受性和生物膜形成等致病增强特征的一个可能的候选者。通过对同基因FSR阳性和FSR阴性粪肠球菌分离株的拟议研究，申请人将(1)研究FSR介导的生物被膜相关基因的转录调控，并评估环境信号(如葡萄糖浓度)如何通过FSR传递以调节生物被膜的形成；(2)表征FSR对β-内酰胺类抗生素诱导的杀伤的自溶和自溶非依赖性机制的调控；以及(3)通过在改良的Robbins装置中开发生物膜来模拟慢性肠球菌感染的条件，以确定FSR如何影响粪肠球菌对β-内酰胺类抗生素、万古霉素和氨基糖苷类抗生素的整体反应。申请者是贝丝以色列女执事医学中心的传染病研究员，将在他的赞助商小罗伯特·C·莫林博士、罗杰·T·井上博士和彼得·F·韦勒的指导下进行这项研究。除了导师指导的研究，申请人的职业发展还将得到哈佛医学院微生物学和遗传学课程的补充，冷泉港实验室的细菌遗传学培训，以及哈佛公共卫生学院的生物统计学课程。本申请的目标是(1)确定肠球菌生物被膜形成和β-内酰胺耐受性的调节，以指导对抗这种日益流行的病原体的策略，以及(2)允许申请人发展成为独立研究人员所需的技能。

DESCRIPTION (provided by applicant): Enterococcus faecalis is a leading cause of endocarditis, nosocomial bacteremia and urinary tract infections. Two characteristics contributing to the difficulty in treating enterococcal infections are (1) tolerance to beta- lactam antibiotics and (2) the propensity to cause biofilm-associated infections. The regulation of beta-lactam tolerance and biofilm formation remains incompletely defined. The applicant for this Research Career Award, Dr. Satish K. Pillai, proposes that the E. faecalis quorum-sensing locus fsr, based on its homology to the Staphylococcus aureus regulator agr, also functions as a global regulator. Using the agr paradigm, fsr represents a likely candidate by which E. faecalis regulates pathogenesis-enhancing characteristics like antibiotic tolerance and biofilm formation. Through proposed studies on isogenic fsr-positive and fsr-negative E. faecalis isolates, the applicant will (1) investigate fsr -mediated transcriptional control of biofilm associated genes and evaluate how environmental cues, such as glucose concentration, are relayed through fsr to modulate biofilm formation; (2) characterize fsr regulation of autolysis-dependent and autolysis-independent mechanisms of beta-lactam induced killing; and (3) simulate the conditions of chronic enterococcal infections by developing biofilms in the modified Robbins Device, in order to determine how fsr influences the overall response of E. faecalis to beta-lactam antibiotics, vancomycin, and aminoglycosides. The applicant is an Infectious Diseases fellow at Beth Israel Deaconess Medical Center, and will conduct this research under the mentorship of his sponsors, Drs. Robert C. Moellering, Jr., Roger T. Inouye and Peter F. Weller. In addition to his mentored research, the applicant's career development will by supplemented by course work in microbiology and genetics at Harvard Medical School, bacterial genetics training at Cold Springs Harbor Laboratory, and biostatistics courses at the Harvard School of Public Health. The goals of this application are to (1) define the regulation of enterococcal biofilm formation and beta-lactam tolerance in order to guide strategies to counter this increasingly prevalent pathogen and (2) allow the applicant to develop the skills needed to be an independent investigator.