VIRULENCE OF A LINEAGE OF UROPATHOGENIC ESCHERICHIA COLI

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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.