An official website of the United States government.
Salmonella is a large group of closely related bacteria that are a major cause of food poisoning in humans and animals. The "host-adapted" Salmonella have evolved to infect particular animals. However,it is not known how Salmonella become adapted to specific hosts, or why some Salmonella cause different disease symptoms. To answer these questions,we plan to analyze the DNA sequence of three important host-adapted Salmonella to identify the genetic differences responsible for their unique host-adaptationand disease symptoms.
Salmonella Pullorum, Salmonella Dublin, and Salmonella Choleraesuis are adapted to different farm animals:S almonella Pullorum infects poultry, Salmonella Dublin infectscattle,and Salmonella Choleraesuis infects pigs. These three Salmonella cause severe, often fatal, diseases in the farm animals. <P>In addition, infected farm animals are a common source of human food poisoning. Each of the serovars shares a core set of common genes, but each serovar also has a set of unique genes that define its distinct virulence properties. To identify these differences, we plan to determine the DNA sequences of the three Salmonella genomes, then compare the genome sequences with each other toidentify unique genes that may be responsible for their distinct virulence properties. Identifying these genetic differences will provide insight into how these pathogens cause disease, and how pathogens acquire new properties that allow infection of a novel host or alter the disease symptoms. This insight will provide a springboard for the development of new approaches to prevent Salmonella infections in farm animals. In addition, because new strains of pathogenic bacteria often arise by infection of a novel host,this insight may help scientists respond to the threat of new, emerging pathogens.