Adhesins for Colonization of Chickens and Their Use in Preventive of Salmonellosis (9702552)

The incidence of infection resulting from food borne pathogens continue to increase worldwide despite extensive research and changes at the production and processing levels. A 1996 CDC study indicated that Salmonella accounted for the majority of the bacterial food borne disease outbreaks from 1988 to 1992. Our long- term objective is to reduce or eliminate Salmonella colonization of poultry, which would in turn, result in a reduction in the shedding of Salmonella in feces, its transmission to eggs, and the cross-contamination which occurs during processing. An understanding of the mechanism of Salmonella adherence to chicken cells could be particularly valuable when developing strategies to eliminate Salmonella contamination of poultry. Our preliminary data support the hypothesis that the Salmonella bacterium expresses gene(s) encoding an "adhesin" protein in response to high iron concentrations, and this adhesin is involved in binding the bacterial pathogen to a host cell. The goals of this proposal are (1) to identify the gene(s) encoding the iron-induced adhesin from Salmonella typhimurium, (2) to evaluate the role of the iron-induced adhesin in the adherence of the Salmonella to avian cells and (3) to determine if the iron-induced adhesin is made by other Salmonella species which colonize chickens. We will identify mutants unable to synthesize this adhesin and these will be evaluated using tissue culture and animal models. Ultimately,this information will be used to design methods to eliminate Salmonella in poultry either by contributing to the development of a live oral vaccine,or by identifying possible changes in the slaughtering procedure to reduce Salmonella cross-contamination.