Project Number: 3625-32000-101-00
Project Type: Appropriated

Start Date: Dec 10, 2010
End Date: Dec 09, 2015

Objective:
1)Identify molecular mechanisms in Salmonella that impact virulence and antimicrobial resistance in the gastrointestinal environment of cattle and swine. 2)Characterize the genetic pathways in swine that respond to Salmonella infection, their relationship to carrier status, and the ability to predict and control Salmonella prevalence and ultimately food safety. 3)Investigate interactions between Salmonella and host microbiota that influence Salmonella colonization and persistence, alter the commensal composition in the host, and provide novel intervention strategies to decrease Salmonella in swine populations.

Approach:
1) Use phenotypic assays, recombineering, and global transcriptional analysis to identify the genes and genetic pathways involved in regulating Salmonella DT104 hyper-invasion in response to a) rumen protozoa and b) sub-inhibitory concentrations of antibiotics. 2) Use an attenuated, LPS/flagella-deficient S. Typhimurium strain to re-focus the pig’s immune response from serovar-specific antigens to conserved antigens during vaccination against Salmonella, thereby providing cross-protection against multiple Salmonella serovars. 3) Classify the porcine gene expression differences between low and high shedders of Salmonella during colonization. 4) Compare the gastrointestinal microbial communities of pigs before, during and after Salmonella colonization to assess correlations with Salmonella shedding status in the pigs.