BACTERIAL SECONDARY METABOLITES DISTINGUISH COMMENSAL AND PATHOGENIC E COLI

这个子项目是许多研究子项目中利用 资源由NIH/NCRR资助的中心拨款提供。子项目和 调查员(PI)可能从NIH的另一个来源获得了主要资金， 并因此可以在其他清晰的条目中表示。列出的机构是 该中心不一定是调查人员的机构。 项目概述：基因组和转录数据表明细菌铁在尿路感染(UTI)发病机制中的重要作用。引起尿路感染的主要原因大肠杆菌从周围环境中获取铁的一种方式是分泌被称为铁载体的铁螯合小分子。虽然所有的大肠杆菌都能够分泌一种名为Enterobactin的祖先铁载体，但许多临床菌株已经获得了分泌和摄取化学上不同的铁载体的基因，这可能在发病机制中具有特殊的作用。我们利用LC-MS-DECA建立了一种LC-MS/MS(MRM)分析方法，用于定性和定量研究不同菌株之间铁载体的产生。这项测试使用稳定的同位素标记来比较通过与华盛顿大学尿路感染研究中心的临床研究人员合作获得的肠道和尿路大肠杆菌分离株。从这项研究中，我们获得了证据表明，尿路病原体通常是根据它们产生两个特定铁载体的最高水平的能力从可用的肠道菌株中挑选出来的。这项试验将用于在最初的临床微生物学研究中鉴定特别毒力的大肠杆菌菌株。有了更灵敏的仪器，我们将跟踪初步的体内数据，以适应这种分析方法，通过直接从患者尿液中检测与毒力相关的铁载体来进行体内诊断。我们打算使用这里开发的质谱学方法来开始临床使用的体内微生物学诊断的试点研究。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Project Summary: Genomic and transcriptional data suggest a prominent role for bacterial iron acquisition during urinary tract infection (UTI) pathogenesis. One means by which Escherichia coli, the major cause of UTI, obtain iron from their surrounding is secretion of small iron-chelating molecules called siderophores. While all E. coli are capable of secreting an ancestral siderophore called enterobactin, many clinical strains have acquired genes for secretion and uptake of chemically distinct siderophores, which may have a special role in pathogenesis. We have used the LCQ-DECA to develop an LC-MS/MS (MRM) assay for qualitative and quantitative studies of siderophore production between E. coli strains. This assay uses stable isotope labeling to compare gut and urinary tract isolates of E. coli obtained through a collaboration with clinical researchers at the University of Washington's Urinary Tract Infection Research Center. From this study, we have obtained evidence suggesting that urinary pathogens are often selected from available gut strains based on their ability to produce the highest levels of two specific siderophores. This assay will be used to identify particularly virulent E. coli strains in initial clinical microbiology studies. With more sensitive instrumentation, we will follow up on preliminary in vivo data to adapt this assay to perform in vivo diagnostics through detection of virulence-associated siderophores directly from patient urine. We intend to use the mass spectrometric approaches developed here to begin pilot studies on in vivo microbiologic diagnostics for clinical use.