Vaccination Against Lawsonia intracellularis Decreases Shedding of Salmonella enterica serovar Typhimurium in Co-Infected Pigs and Alters the Gut Microbiome

Salmonella enterica is a leading cause of foodborne illness worldwide and pork can serve a source of infection. In this study, we investigated if vaccinating pigs against Lawsonia intracellularis, a common pathogen of swine that has previously been shown to favor Salmonella enterica infection, confers protection against Salmonella enterica serovar Typhimurium. We investigated the underlying changes in the gut microbiome mediated by single S. Typhiumurium infection compared to co-infection with L. intracellularis as well as the effect of vaccination on the microbiome. In this study, a total of five treatment groups were used: 1) challenged with S. Typhimurium alone (Sal), 2) challenged with both S. Typhimurium and L. intracellularis (Sal Law), 3) challenged with S. Typhimurium and vaccinated against L. intracellularis (Sal Vac), 4) challenged with both S. Typhimurium and L. intracellularis and vaccinated against L. intracellularis (Sal Law Vac), and 5) non-infected control (Control).