Novel virulence and exoenzyme regulators

描述（由申请人提供）：细菌性角膜炎是一种导致视力丧失和失明的全球性问题，费用高昂，粘质沙雷氏菌是社区获得性革兰氏阴性细菌性角膜炎的主要病原体。S.粘质杆菌还引起许多医院获得性感染，包括肺炎、心内膜炎、菌血症和尿路感染，这些感染通常对当前的抗生素具有抗性，并且其结果与显著的发病率和死亡率相关。缺乏研究，调查如何S。使用同基因突变菌株，粘质杆菌基因导致眼部感染。这项研究的广泛的长期目标是预防由这种生物体引起的角膜感染后的视力丧失。通过对S.调节粘质虫毒力因子的方法将允许一种新的方法来减少由这些因子的表达引起的组织损伤和角膜混浊。这些关于特定途径的新知识可用于定制设计新型抗感染药物。建立新的治疗靶点变得越来越重要，因为细菌继续对现有类别的抗生素产生耐药性。我们的总体具体假设是要测试的转录因子EepR/S是一个关键的毒力因子，控制组织损伤金属蛋白酶和溶血素活性的表达。我们的初步数据支持S. marcescens严重减弱了S.在角膜炎的体内眼部模型中的粘质杆菌。我们的中心假设将通过实现以下目标来检验：目标1。检验EepR/S、四种金属蛋白酶和ShlA溶血素是S.粘质虫体外细胞毒性和体内眼部致病性。目标2.检验EepR和EepS调控金属蛋白酶和溶血素基因转录的假设，以及EepR/S与其他转录因子（crp、hexS和pigP）处于调控通路中的假设。

DESCRIPTION (provided by applicant): Bacterial keratitis is a costly and global problem that results in vision loss and blindness, and Serratia marcescens is a leading agent of community-acquired Gram-negative bacterial keratitis. S. marcescens also causes many hospital acquired infections including pneumonia, endocarditis, bacteremia and urinary tract infections that are commonly resistant to current antibiotics and whose outcomes are associated with significant morbidity and mortality. There is a lack of studies that investigate how S. marcescens genes contribute to ocular infections using isogenic mutant strains. The broad long-term objective of this research is to prevent vision loss following corneal infections caused by this organism. A better understanding of the mechanisms by S. marcescens virulence factors are regulated will allow for a novel approach to reduce tissue damage and corneal opacification that results from the expression of these factors. This new knowledge about specific pathways can be used to custom design novel anti-infectives. Establishing new therapeutic targets is becoming ever more important as bacteria continue to develop resistance to existing classes of antibiotics. Our overall specific hypothesis to be tested is that the transcription factor EepR/S is a critical virulence factor that controls expression of tissue damaging metalloprotease and hemolysin activities. Our preliminary data supports that the mutation of EepR/S in S. marcescens severely attenuates the pathogenesis of S. marcescens in an in vivo ocular model of keratitis. Our central hypothesis will be tested by accomplishing the following aims: Aim 1. Test the hypothesis that EepR/S, four metalloproteases and the ShlA hemolysin are required for S. marcescens cytotoxicity in vitro and ocular pathogenesis in vivo. Aim 2. Test the hypothesis that EepR and EepS regulate transcription of metalloprotease and hemolysin genes, and that EepR/S is in a regulatory pathway with other transcription factors (crp, hexS and pigP).