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<OL> <LI> Describe and characterize sites, mechanisms, and Stx-mediated effects of STEC
colonization of cattle intestines; <LI> Analyze in vivo gene expression of STEC O157:H7
using genomic techniques to identify genes involved in expression and regulation of
adherence, colonization, and shedding; <LI>Develop and test the efficacy of
intervention strategies for reducing colonization and shedding of STEC O157:H7; <LI>Identify mechanisms of E. coli adherence involved in postweaning colibacillosis in
pigs.
Approach:
Experimental animal infections and genomic technologies will be used to identify specific STEC genes necessary for colonization and persistence in animals, and to identify and test interventions directed against identified targets. Weaned calves and neonatal pigs will be experimentally inoculated with E. coli. Microbiologic, histologic, and immunologic methods will be used to identify colonization sites and mechanisms of host-pathogen interactions. Biochemical, immunologic, and molecular biologic techniques will be used to identify specific STEC genes necessary for colonization and persistence in animals, and to identify and test interventions (vaccines and antimicrobials) directed against identified targets. Genetic, molecular, and immunologic techniques will be used to identify and characterize bacterial adhesins and other virulence factors of E. coli pathogens which cause diarrhea and edema disease in postweaning swine and evaluate their usefulness as targets for diagnostic assays or immunogens to prevent colibacillosis in swine. IBC-0094 BSL-2; Recertified 10/08/09; IBC-0180 BSL-2; Recertified 10/08/09.