Project Number: 3625-32000-078-00
Project Type: Appropriated

Start Date: Dec 10, 2005
End Date: Dec 09, 2010

Objective:
(1) Investigate the molecular mechanisms that coordinate virulence and antibiotic resistance in Salmonella obtained from cattle (DT104 and S. dublin) and swine (DT104 and S. choleraesuis). (2) Characterize the molecular mechanisms involved in Salmonella survival, colonization and pathogenicity in relation to various host (swine and cattle) factors such as stress, gastric pH, and protozoa. (3) Investigate the molecular basis for swine resistance to Salmonella colonization by characterizing the immunological aspects of infection.

Approach:
(1) Use a novel reporter system and transposon mutagenesis o identifiy DT104 genes involved in rumen protozoa-mediated hypervirulence. (2) Use an in vitro conjugation system to chracterize intra-protozoal transfer of plasmids from Klebsiella (and other bacteria) to Salmonella. (3) Compare the progression of salmonellosis for defaunated and fully-faunated calves infected with DT104. (4) Functional genomic analyses will be performed on Salmonella exposed to norepinephrine, low pH, and conditions relevant to intestinal colonization. (5) Use microarrays to identify swine genes that contribute to innate resistance to Salmonella colonization. IBC-0210R BSL-Exempt; Recertified 10/22/07.