The roles of fosfomycin resistant subpopulations of Escherichia coli in urinary tract infection.

项目概要/摘要 尿路感染（UTI）是全世界最常见的细菌感染之一， 因为他们对一线抗生素的抗药性越来越强。因此，最后的抗生素，如 磷霉素开始被更频繁地开处方。尿路致病性大肠杆菌（UPEC）， 尿路感染的主要原因，可以成为耐磷霉素，通过突变，损害功能或 UhpT转运蛋白的产生，其将磷霉素输入细菌细胞。目前的模式是 这种突变是以适应性为代价的，因为UhpT的受损限制了糖酵解的输入， 中间体葡萄糖-6-磷酸。然而，我的初步数据表明，导致 通过消除uhpT表达而增加对磷霉素的抗性，不妨碍宿主的定殖 泌尿系统事实上，磷霉素输入的损失表明在长期感染期间持续性增加。 此外，我已经表明，77%的筛选UPEC临床分离株具有磷霉素耐药， 亚群这就提出了一个令人担忧的假设，即磷霉素耐药亚群的出现， 在UTI期间，可能是对宿主施加的压力的反应，并可能提供额外的健身 病原体的优势。我将通过两个具体目标来检验这一假设，这两个目标将： 磷霉素耐药亚群对UPEC发病机制的贡献（目的1），并阐明 uhpBA丧失后，UPEC发病过程中菌尿延长（目的2）。我的研究将 提供的见解，将最终帮助我们遏制耐药性的发生和传播，以最后一个- 通过彻底阐明导致磷霉素耐药的新机制， 感染，并测量其适合性的优点和缺点相比，他们的父母株。 通过这些目标的执行，我将培养在基因组分析，先进的显微镜， 技术、真核细胞培养和宿主-病原体相互作用的综合分析。

PROJECT SUMMARY/ABSTRACT Urinary tract infections (UTIs) are one of the most common bacterial infections worldwide and the bacteria that cause them are becoming increasing resistant to frontline antibiotics. As a result, last resort antibiotics, like fosfomycin, are beginning to be more frequently prescribed. Uropathogenic Escherichia coli (UPEC), which is the primary cause of UTIs, can become resistant to fosfomycin, through mutations that impair the function or production of the UhpT transporter, which imports fosfomycin into the bacterial cell. The current paradigm is that such mutations come at a fitness tradeoff because impairment of UhpT limits the import of the glycolysis intermediate glucose-6-phosphate. However, my preliminary data indicate that mutations that lead to increased resistance to fosfomycin by abrogating uhpT expression, do not impede colonization of the host urinary tract. In fact, loss of fosfomycin import demonstrates increased persistence during long-term infection. Additionally, I have shown that 77% of screened UPEC clinical isolates harbor fosfomycin resistant subpopulations. This raises the alarming hypothesis that fosfomycin resistant subpopulations arise during UTI, possibly in response to a host-imposed stress and may provide additional fitness advantages for the pathogen. I will test this hypothesis through two specific aims which will: determine the contribution of fosfomycin resistant subpopulations to UPEC pathogenesis (Aim 1) and elucidate the basis of prolonged bacteriuria during UPEC pathogenesis following loss of uhpBA (Aim 2). Together my studies will provide insights that will ultimately help us curb the onset and propagation of resistance to one of the last- resort antibiotic agents, by thoroughly elucidating novel mechanisms that lead to fosfomycin resistance during infection and gauging their fitness advantages and disadvantages in comparison to their parental strains. Through the execution of these aims, I will cultivate valuable skills in genomic analysis, advanced microscopy techniques, eukaryotic cell culture, and comprehensive analysis of host-pathogen interactions.