ALTERNATIVE APPROACHES FOR E FAECALIS INFECTIONS

超出提供的空间。肠球菌是引起心内膜炎的3个最常见的原因，仅次于链球菌和葡萄球菌，是医院获得性感染的2-3个最常见的原因，其中粪肠球菌是主要的分离菌种。抗生素耐药性可能会促进医院感染中肠球菌的形成，并肯定会增加成功治疗患者的难度，特别是那些患有心内膜炎的患者。该项目的中心假设是，通过更好地了解肠球菌，可以开发新的治疗或预防方法。在之前资助的一项赠款中，研究人员发现并鉴定了一些抗原性编码基因；一个似乎影响小鼠对病毒的抵抗力的多糖基因簇(EPA)；不同的附着性表型和一个似乎参与粘附性的基因ace；以及一个与辅助基因调节器(Agr)基因座或葡萄球菌同源的基因位点，该基因涉及粪肠球菌明胶酶和塞纳蛋白水解酶的表达，后者也影响小鼠的毒力。在这一应用中，我们提出m来验证粪肠球菌a^R基因座是否调节GLE和spE，并确定它们是否对毒力都是重要的；调查这些基因在粪肠球菌中的分布；并确定肠球菌Aer样基因是如何调节的，以及它是否像葡萄球菌agr一样调节其他基因。我们还计划(2)检验这一假设，即Ace(一种新描述的肠球菌胶原粘附剂)是我们报道的粘附性的原因，并且对毒力很重要；探索Ace产生的调节；以及确定Ace变异的分布和影响，如果Ace在人类中引起感染粪肠球菌的抗体反应(使用重组Ace和患者血清)，并且感染期间产生的抗体或重组Ace的抗体是否具有保护性。在我们的第三个具体目标中，我们计划(3)确定多糖基因簇是否是最近描述的一种粘液表型的原因，研究其调节，并进一步测试其对外来物质的黏附、毒力和保护的贡献。我们还将探索一种使用互选来构建非极性Dele^n突变体的系统，该系统基于我们先前对粪肠球菌PYR基因的工作，并探索有助于我们避免LETHY模型的额外方法。我们希望这项工作的结果将为我们寻求预防、控制或抗击粪肠球菌感染的甲基消耗臭氧层物质提供坚实的线索。表演网站========================================Section End===========================================

EXCEED THE SPACE PROVIDED. Enterococci are the 3 most common cause of endocarditis, behind streptococci and staphylococci, and the 2-3 most common cause of hospital acquired infections, with Enterococcusfaecalis being the predominant species isolated. Antimicrobial resistance likely facilitatesthe establishment of enterococci in nosocomial infec- tions and certainly makes it more difficult to successfullytreat patients, particularly those with endocarditis. The central hypothesis of this project is that by better understanding enterococci, new therapeutic or preventative mo- dalities can be developed. Work during a previously funded grant identified and characterized a number of anti- gen encoding genes; a polysaccharide gene cluster (epa) that appears to influencevirulence in mice; different ad- herence phenotypes and a gene, ace, that appears to be involved in adherence; and a gene locus with homology to the accessory gene regulator (agr) locus or staphylococci that is involved in expression of an E. faecalis gelati- nase and a senne protease that also influence virulence in mice. In this application, we propose m to verify that the E.faecalis a^r-like locus regulates gelE and sprE and determine if all are important for virulence;to investi- gate the distribution of these genes among E. faecalis; and to determine how the enterococcal aer-like locus is regulated and if it, like the staphylococcal agr, regulates other genes. We also plan (2) to test the hypothesis that Ace (a newly described adhesm for collagen of enterococci) is the cause of the adherence we haye reported and is important for virulence; to explore the regulation of Ace production; and to determine the distribution and effect of variations in ace, if Ace elicits an antibody response in humans (using recombinantAce and patient sera) in- fected by E.faecalis and if antibody made during infection, or antibody to recombinant Ace, is protective. In our third specific aim, we plan (3) to establish if the polysaccharide gene cluster is the cause of a recently described mucoid phenotype, to study its regulation, and to further test its contribution to adherence to foreign material, virulence and protection. We will also explore a system for constructing non-polar dele^n mutants usingcoun- terselection, based on our prior work with the E.faecalis pyr genes, and to explore additionalassays thatwould help us avoid lethalitymodels. We hope that results from this work will provide solid leads in our quest for meth- ods to prevent, control, or combat E.faecalis infections. PERFORMANCE SITE ========================================Section End===========================================