Characterization of viridans group streptococci from endophthalmitis

项目摘要/摘要 绿色链球菌被经典地认为是具有致龋性的口腔共生菌；然而，这些 细菌也被列为最常见的引起细菌性眼内炎的物种之一。外源 细菌性眼内炎可发生在创伤、眼科手术或眼部注射后。使用的是抗生素 然而，要治疗这种疾病，抗生素只能杀死细菌，而不能改善对 眼睛。链球菌的种类尤其与非常差的视觉结果有关；尽管接受了治疗， 通常发生内脏摘除或眼球摘除。这个应用程序直接目标是描述 绿色链球菌眼内炎菌株及其毒力因子的鉴定。这个目标是 旨在启动对确定发病机制的更广泛的、长期的目标的研究 并确定未来治疗的潜在靶点。两个主要目标是 建议：1)探讨细菌蛋白水解酶HtrA在眼内炎中的作用，并测定其玻璃体和 细菌蛋白底物，以及2)分析眼内炎的盘根组和毒力转录组- 造成了菌株。第一个目标将通过对从HtrA克隆的重组HtrA变体的功能分析来测试 绿色杆菌菌株和htrA阳性菌株的htrA的缺失突变，以及htrA基因的添加 HtrA对htrA阴性菌株。第二个目标将使用21个菌株的全基因组测序，然后是 生物信息学泛基因组分析以确定整个集合中的保守基因，以及体内和 在体外测定这组物种的毒力转录组。实现这些目标将 跳板：确定与这些物种的眼部感染有关的关键因素。这项研究是 预计将使患者的眼睛健康长期受益，因为所获得的知识有助于未来 治疗方面的发展。

Project Summary/Abstract The viridans streptococci are classically considered oral commensals with cariogenic potential; however, these bacteria are also listed among the most common species that cause bacterial endophthalmitis. Exogenous bacterial endophthalmitis can occur following trauma, ocular surgery, or ocular injections. Antibiotics are used to treat this disease, however, antibiotics are only able to kill the bacteria and do not ameliorate the damage to the eye. Streptococcal species in particular are associated with very poor visual outcomes; despite treatment, evisceration or enucleation commonly occur. The immediate objective of this application is to characterize endophthalmitis strains of the viridans streptococci and identify their virulence factors. This objective is intended to initiate study into the broader, long-term objectives of determining the mechanisms of pathogenesis of this important group of species and identify potential targets for future therapies. Two major aims are proposed: 1) to investigate the role of bacterial protease HtrA in endophthalmitis and determine its vitreous and bacterial protein substrates, and 2) to analyze the pangenome and virulence transcriptome of endophthalmitis- causing strains. The first aim will be tested by function analysis of recombinant HtrA variants cloned from the viridans strains and by deletion mutagenesis of htrA from htrA-positive strains, as well as genetic addition of htrA to htrA-negative strains. The second aim will employ whole genome sequencing of 21 strains followed by bioinformatics pangenome analysis to identify conserved genes across the collection, and RNA-seq in vivo and in vitro to determine the virulence transcriptome of this group of species. Accomplishment of these aims will springboard the identification of key factors involved in ocular infection by these species. This research is expected to benefit patient ocular health in the long-term because the knowledge to be gained can aid future therapeutic development.