D-serine/DsdCXA Control of E. coli Uropathogenesis

大肠埃希菌是社区获得性尿路感染（UTI）的最常见原因， 导致医院内尿路感染和败血症据估计，每年有800万名医生就诊， 在美国，UTI的发病率和费用都很高（> 10亿美元）。我们测试的 推测致病性基因可能与五年威胁性大肠杆菌的致病有关。肠外大肠 感染，如肾盂肾炎和脓毒症，可以通过比较 尿脓毒症E. coli菌株CFT073与E.大肠杆菌实验室菌株MG 1655或O157：H7菌株EDL 933。 我们鉴定了> 300个CFT073特异性基因座。D-丝氨酸周围区域的继续研究 脱氨酶基因（dsdCXA）的研究尤其引人注目。dsdA的等位基因敲除突变体，其编码 D-丝氨酸脱氨酶在1型菌毛介导的粘附中的表达没有改变，但增加了300倍 竞争性比野生型菌株在膀胱或肾脏的殖民感染的小鼠在上升 UTI模型DsdC是dsdXA转录的阳性效应子，并且是DsdA的lysR家族的成员。 监管部门通过体内和体外基因表达技术，我们将测试假设，D-丝氨酸 通过与dsdC或其他共同效应物的相互作用，影响多个基因的表达， 影响疾病鼠模型中CFT073发病机制。我们还将确定环境 条件和影响dsdCXA基因表达的其它基因。两个基因 候选物是ipuAB（泌尿病原体的整合酶样t2蛋白），其紧邻于 在CFT073和其它泌尿系致病性大肠杆菌的染色体上存在dsdCXA基因。coll. ipuAB是同系物 在1型皮利相位开关重组酶中，fimB和fimE连接并控制 急诊大肠杆菌1型菌毛操纵子。我们将测试这些基因提供额外的 控制dsdCXA或其他未知基因表达的相位开关系统。的目的 本研究拟对大肠杆菌的关键毒力基因进行鉴定。大肠杆菌感染严重 人类疾病。这些信息将用于开发新的化疗药物和疫苗 战略布局

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.