The Role of Enterococcus Unique Hypothetical EF1909 in Intrinsic β-lactam Resistance

项目概要： 肠球菌是多重耐药医院获得性感染的主要原因-第一个E ESKAPE的缩写。我们最近发现，肠球菌属与其最接近的 现存的祖先进化出了增强的生存特征，包括饥饿和 干燥，以及通过抗生素和其他针对细胞表面的杀生物剂的挑战。 也就是说，在与数亿年前的祖先不同的过程中， 细胞更加坚固和不可渗透。我们发现肠球菌拥有10个基因， 罕见或不存在于属外。此外，我们发现，其中一个，编码一个 假设的蛋白质，有助于对β-内酰胺类的内在抗性-最大的一类 用于人类医学的抗生素。由于这种内在的耐药性，这类抗生素具有 在控制肠球菌感染方面用途有限。在这里，我们建议验证 初步结果表明，这种基因，称为EF 1909，有助于内在的b-内酰胺 抗性，并更严格和全面地评估缺乏这种抗性的细胞的表型 功能.我们还评估了EF 1909在生长周期中何时表达，并确定了 它的存在/不存在是否导致细胞壁肽聚糖的组成改变， 通过其对固有的β-内酰胺抗性的贡献。如果我们能证实初步证据 表型指标的探索性工作，这将提高然后筛选的前景 对于EF 1909抑制剂，预计将使肠球菌现在容易受到廉价的 和容易获得的β-内酰胺抗生素。使肠球菌易于通过β-内酰胺类药物治疗 将是对全球健康产生重大影响的一个进步。

Project summary: Enterococci are leading causes of multidrug resistant hospital acquired infection – the first E in the ESKAPE acronym. We recently showed that the genus Enterococcus differs from its closest extant ancestors in having evolved enhanced traits for survival, including to starvation and desiccation, as well as to challenge by antibiotics and other biocides that target the cell surface. That is, in diverging from its ancestors hundreds of millions of years ago, it gained features making the cell more rugged and impermeable. We found that enterococci possess 10 genes that are rare or do not exist outside of the genus. Moreover, we found that one of these, encoding a hypothetical protein, contributes to intrinsic resistance to b-lactams – the largest class of antibiotics used in human medicine. As a result of this intrinsic resistance, this antibiotic class has been of limited use in controlling enterococcal infection. Here we propose to validate the preliminary results implicating this gene, termed EF1909, in contributing to intrinsic b-lactam resistance and more rigorously and fully assess the phenotype of cells engineered to lack this feature. We additionally assess when in the growth cycle that EF1909 is expressed and determine whether its presence/absence results in cell wall peptiglycan of altered composition as implicated by its contribution to intrinsic b-lactam resistance. If we are able to substantiate the preliminary indications of phenotype in this exploratory work, this would raise the prospect of then screening for EF1909 inhibitors that would be predicted to render enterococci now vulnerable to inexpensive and readily available b-lactam antibiotics. Rendering enterococci readily treatable by b-lactams would be an advance of very high impact for global health.