VIRULENCE OF A LINEAGE OF UROPATHOGENIC ESCHERICHIA COLI

该项目广泛的长期目标是 明确上行性泌尿系疾病的发病机制 尿路感染UTI）的原型尿路致病性菌株J96 大肠杆菌P的神秘的I类和III类变体 粘附素分子PapG，并描绘了 J96样克隆的程度、宿主范围和疾病关联 尿致病性E.大肠杆菌的成员 拥有一种或两种PapG粘附素 具体目标是：（1）建立一个和两个- 野生型"J96样"大肠杆菌菌株的"敲除" PapG突变体 以及每种物质的重组衍生物，并评估其 上升型UTI小鼠模型中的尿毒力;和2） 确定原型尿路致病性菌株J96的相关性， 从北卡罗来纳州精心挑选的动物和人类大肠杆菌分离株 美国和欧洲。 实验设计和方法：PapG突变体 将使用自杀质粒在"J96样"菌株CP9中构建 等位基因交换系统，并将重建为 合适的papG基因型。 将对这些衍生物进行尿毒力试验， 与野生型亲本菌株在已建立的小鼠模型中， 上行性尿路感染 此外，225个临床大肠杆菌分离株， 来自已知人类和动物来源的血清群O4将被 评价了与J96在多个方面的相似性 通过使用聚合酶链区分特征 基于反应（PCR）的基因组指纹图谱，O：K：H; F 血清分型和基于PCR的三种papG等位基因检测， 细胞毒性坏死因子1（chf 1）和需氧菌素（aer）的基因。 该项目的健康性在于 需要更好地了解1）的毒力机制 导致UTI的大肠杆菌菌株，以及2）这些菌株的地理分布 分布和致病行为。 这些信息将加速 制定预防UTI和相关疾病的措施 感染. 由于J96菌株的毒力已被广泛研究， 进一步阐明J96的毒力机制， “J96样”菌株的临床行为的澄清，将扩大 关于应变的现有信息的有用性 J96

THE PROJECT'S BROAD, LONG TERM OBJECTIVES are to define the contributions to the pathogenesis of ascending urinary tract infection UTI) of prototypic uropathogenic strain J96's enigmatic Class I and Class III variants of the Escherichia coli P firmbrial adhersin molecule PapG, and to delineate the geographic extent, host range, and disease associations of a J96-like clonal group of uropathogenic E. Coli whose members characteristically possess one or both of these PapG adhesins. THE SPECIFIC AIMS are 1) to construct single and double- "knockout" PapG mutants of a wildtype "J96-like" E.coli strain and reconstituted derivates of each, and to evaluate their urovirulence in a mouse model of ascending UTI; and 2) to determine the relatedness ot prototypic uropathogenic strain J96 of carefully selected animal and human E.coli isolates from North America and Europe. EXPERIMENTAL DESIGN AND METHODS: PapG mutants will be constructed in "J96-like" strain CP9 using a suicide plasmid allele exchange system and will be reconstituted for the appropriate papG genotype using recombinant papG plasmids. These derivatives will be tested for urovirulence in comparison with the wild-type parent strain in an established mouse model of ascending UTI. In addition, 225 clinical E.coli isolaates of serogroup O4 from known human and animal sources will be evaluated for similarities to J96 with respect to multiple differentiating characteristics through the use of polymerase chain reaction- (PCR-) based genomic ifingerprinting, O:K:H;F serotyping, and PCR-based detection of the three papG alleles and genes for cytotoxic necrotizing factor 1 (chf1) and aerobactin (aer). THE HEALTH RELATEDNESS OF THE PROJECT lies in the need for a better understanding of 1) the virulence mechanisms of the Ecoli strains that cause UTI, and 2) these strains' geographic distribution and pathogenic behavior. Such information will speed the development of preventive measures against UTI and related infections. Since the virulence of strain J96 has been extensively studied, further elucidation of J96's virulence mechanisms, and clarification of the clinical behavior of "J96-like" strains, will extend the usefulness of the already-available information regarding strain J96.