Intrinsic Resistance to antimicrobials in Enterococcus faecalis

描述(申请人提供)：耐药的革兰氏阳性细菌，如粪肠球菌和金黄色葡萄球菌，是医院感染的主要原因。粪肠球菌是一种成功的医院获得性病原体，部分原因是它对针对细菌细胞膜生物发生的常用抗生素具有内在耐药性。然而，许多关于粪肠球菌内在耐药性的遗传和生化基础的问题仍然没有得到回答。初步研究发现了一种新的信号转导系统，该信号转导系统含有真核型丝氨酸/苏氨酸激酶(PrkC)，是粪肠球菌产生内在耐药性所必需的。我们假设PrkC监测被膜活性抗生素引起的细胞被膜的扰动，并介导一种适应性生物反应来产生抗菌素耐药性。我们的长期目标是了解这个新的信号系统在介导耐药性方面的作用，更广泛地说，了解粪肠球菌内在耐药性的遗传和生化基础。这项建议的目的是开始阐明信号转导，特别是PrkC通路在介导肠球菌内在耐药中的作用。为了实现这一目标，我们将：1)定义PrkC依赖的调节电路；2)确定PrkC磷酸化的直接底物；3)表征内在抗菌素耐药性的效应因子(PrkC依赖的信号输出)。因此，这里提出的研究将提供对新的细菌信号系统的功能的见解，加强对革兰氏阳性细菌耐药机制的基本了解，并为未来开发针对耐药细菌感染的创新疗法奠定基础。 公共卫生相关性：耐抗生素细菌，如粪肠球菌和金黄色葡萄球菌，是医院获得性感染的主要原因。这里提出的研究将加强对革兰氏阳性细菌耐药机制的基本了解，并为未来努力开发针对耐药细菌感染的创新疗法奠定基础。

DESCRIPTION (provided by applicant): Antibiotic-resistant Gram-positive bacteria, such as Enterococcus faecalis and Staphylococcus aureus, are major causes of hospital-acquired infections. E. faecalis is a successful hospital-acquired pathogen partly due to its intrinsic resistance to commonly used antibiotics that target bacterial cell envelope biogenesis. However, many questions regarding the genetic and biochemical basis for intrinsic antimicrobial resistance in E. faecalis remain unanswered. Preliminary studies identified a new signal transduction system containing a eukaryotic-type Ser/Thr kinase (PrkC) that is required for intrinsic antimicrobial resistance in E. faecalis. We hypothesize that PrkC monitors the cell envelope for perturbations caused by envelope-active antibiotics and mediates an adaptive biological response to produce antimicrobial resistance. Our long-term goal is to understand the role of this new signaling system in mediating resistance, and more generally, the genetic and biochemical basis for intrinsic antimicrobial resistance in E. faecalis. The objective of this proposal is to begin to elucidate the role of signal transduction, and specifically of the PrkC pathway, in mediating intrinsic antimicrobial resistance in enterococci. To achieve this goal, we will: 1) Define the PrkC-dependent regulatory circuit; 2) Identify direct substrates for phosphorylation by PrkC; and 3) Characterize effectors of intrinsic antimicrobial resistance (the output of PrkC-dependent signaling). Thus, the research proposed here will provide insights into the function of a new bacterial signaling system, enhance fundamental understanding of the mechanisms responsible for antimicrobial resistance in Gram- positive bacteria, and form the foundation for future efforts to develop innovative therapies against infections caused by resistant bacteria. PUBLIC HEALTH RELEVANCE: Antibiotic-resistant bacteria, such as Enterococcus faecalis and Staphylococcus aureus, are major causes of hospital-acquired infections. The research proposed here will enhance fundamental understanding of the mechanisms responsible for antimicrobial resistance in Gram-positive bacteria and form the foundation for future efforts to develop innovative therapies against infections caused by resistant bacteria.