D-serine/DsdCXA Control of E. coli Uropathogenesis

大肠埃希氏菌是社区获得性尿路感染(UTI)的最常见原因， 院内尿路感染和败血症的主要原因。据估计，每年有800万人次去看医生。 美国的尿路感染与相关的发病率和费用显著相关(&gt；10亿美元)。我们测试了 毒力基因与威胁FIFE的肠外大肠杆菌致病机制有关的假说 感染，如肾盂肾炎和脓毒症，可以通过比较 尿毒症大肠杆菌CFT073菌株对大肠杆菌实验室菌株MG1655或O157：H7菌株EDL933的影响。 我们确定了&gt；300个CFT073特异的基因座。D-丝氨酸周围区域的继续研究 脱氨酶基因(DsdCXA)尤其引人注目。DsdA的一种等位基因敲除突变体，编码 D-丝氨酸脱氨酶在1型菌毛介导的黏附中的表达没有改变，但增加了300倍 在向上感染的小鼠的膀胱或肾脏定植方面比野生型更具竞争力 UTI模型。DsdC是dsdXA转录的正效应因子，是DsdXA的lysR家族成员之一。 监管者。通过体内和体外基因表达技术，我们将检验D-丝氨酸 通过与双链DC或其他共效应器的相互作用，直接影响多个基因的表达 对小鼠疾病模型CFT073发病机制的影响我们还将确定环境 影响dsdCXA基因表达的条件和其他基因。两个这样的基因 候选的是ipuAB(尿路病原体的整合酶样t2roteins)，它与 CFT073和其他致尿性大肠杆菌染色体上的dsdCXA基因。IpuAB是同系物 在与之连锁并控制其表达的1型菌毛相开关重组酶中，有FIMB和FIME E.Coli1型菌毛操纵子。我们将检验这样一种假设，即这些基因提供了额外的 控制dsdCXA或其他未知基因表达的相位切换系统。该计划的目标是 拟议的项目是识别和表征与严重急性呼吸综合征有关的大肠杆菌的关键毒力基因。 人类疾病。这些信息将用于新的化疗药物和疫苗的开发。 战略。

Escherichia coE is the most common cause of community acquired urinary tract infection (UTI) and a leading cause of nosocomial UTIs and sepsis. There are an estimated 8 million physician visits per year in the U.S for UTIs with significant associated morbidity and expense (> $1,000,000,000). We tested the hypothesis that virulence genes responsible for the pathogenesis of fife-threatening E. coli extraintestinal infections, such as pyelonephritis and sepsis can be identified by comparison of the genome sequence of urosepsis E. coli strain CFT073 to either E. coli laboratory strain MG1655 or O157:H7 strain EDL933. We identified >300 CFT073-specific loci. The continued study of the region surrounding the D-serine deaminase genes (dsdCXA) is especially compelling. An allelic knockout mutant of dsdA which encodes D-serine deaminase, is unaltered in expression of type 1 pili-mediated adherence, but 300-fold more competitive than the wild type strain in colonizing the bladder or kidney of mice infected in an ascending model of UTI. DsdC is a positive effector of dsdXA transcription and a member of the lysR-family of regulators. By in vivo and in vitro gene expression techniques we will test the hypotheses that D-serine through interaction with either dsdC or other co-effectors affects expression of multiple genes that directly influence CFT073 pathogenesis in murine models of disease. We will also identify environmental conditions and additional genes that affect the expression of the dsdCXA genes. Two such gene candidates are ipuAB (integrase-like t2roteins of _uropathogens) that are immediately adjacent to the dsdCXA genes in the chromosome of CFT073 as well as other uropathogenic E. coll. ipuAB are homologs of the type 1 pili phase-switch recombinases,fimB andfimE that are linked to and control expression of the E. coli type 1 pilusfim operon. We will test the hypothesis that these genes provide an additional phase-switch system that controls expression of dsdCXA or other unknown genes. The objective of the proposed project is to identify and characterize critical virulence genes for E. coli involved in serious human diseases. This information will be of use for the development of new chemotherapeutic and vaccine strategies.