PDF(Pubmed)
Abstract：
Urinary tract infections (UTI) account for a substantial financial burden globally. Over 75% of UTIs are caused by uropathogenic Escherichia coli (UPEC), which have demonstrated an extraordinarily rapid growth rate in vivo. This rapid growth rate appears paradoxical given that urine and the human urinary tract are relatively nutrient-restricted. Thus, we lack a fundamental understanding of how uropathogens propel growth in the host to fuel pathogenesis. Here, we used large in silico, in vivo, and in vitro screens to better understand the role of UPEC transport mechanisms and their contributions to uropathogenesis. In silico analysis of annotated transport systems indicated that the ATP-binding cassette (ABC) family of transporters was most conserved among uropathogenic bacterial species, suggesting their importance. Consistent with in silico predictions, we determined that the ABC family contributed significantly to fitness and virulence in the urinary tract: these were overrepresented as fitness factors in vivo (37.2%), liquid media (52.3%), and organ agar (66.2%). We characterized 12 transport systems that were most frequently defective in screening experiments by generating in-frame deletions. These mutant constructs were tested in urovirulence phenotypic assays and produced differences in motility and growth rate. However, deletion of multiple transport systems was required to achieve substantial fitness defects in the cochallenge murine model. This is likely due to genetic compensation among transport systems, highlighting the centrality of ABC transporters in these organisms. Therefore, these nutrient uptake systems play a concerted, critical role in pathogenesis and are broadly applicable candidate targets for therapeutic intervention.
摘要：
尿路感染（UTI）在全球范围内造成了巨大的经济负担。超过75％的UTI是由尿路致病性大肠杆菌（UPEC）引起的，在体内表现出非常快速的生长速度。考虑到尿液和人的泌尿道营养相对受限，这种快速的生长速率似乎是矛盾的。因此，我们缺乏对尿路病原体如何推动宿主生长以促进致病机理的基本了解。这里,我们用了大的硅片，在体内，和体外筛选，以更好地了解UPEC转运机制的作用及其对尿路发病机制的贡献。对注释的转运系统的计算机分析表明，转运蛋白的ATP结合盒（ABC）家族在尿路致病性细菌物种中最保守，表明他们的重要性。与计算机模拟预测一致，我们确定ABC家族对泌尿道的适应性和毒力做出了显著贡献：这些在体内的适应性因子（37.2％）液体介质（52.3%），和器官琼脂（66.2%）。我们通过产生框内缺失来表征在筛选实验中最常见缺陷的12个运输系统。在尿毒力表型测定中测试了这些突变构建体，并产生了运动性和生长速率的差异。然而,在联合攻击小鼠模型中,需要删除多个转运系统以实现实质性的适应性缺陷.这可能是由于运输系统之间的遗传补偿，强调ABC转运蛋白在这些生物体中的中心地位。因此,这些营养吸收系统发挥协同作用，在发病机制中起关键作用，是治疗干预的广泛适用的候选靶标。
