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<p>Salmonella enterica is a major food borne pathogen and is frequently carried by swine. Epidemiologic evidence and our preliminary data indicates that carriage of S. enterica by pigs is enhanced by infection with the pig pathogen Lawsonia intracellularis. The overall goal of the current study is to develop an novel intervention to control S. enterica in pigs by vaccinating them againstL. intracellularis.</p><p>There are three specific aims of this study.</p><p> 1) to determine the duration and quantity of S. enterica shed by pigs infected with S. Typhimurium or S. Typhimurium and L. intracellularis,</p><p> 2) todetermine the effect of vaccination against L. intracellularis on shedding S. Typhimurium, and</p><p> 3) todetermine intestinal microbiome changes in pigs that are singly and dually infected and with or without vaccination.</p>
<p>In the first specific aim, we will be confirming thatL. intracellularisenhances shedding ofS. entericahow long during the growth of pigs shedding remains elevated. To perform this work, pigs will be challenged orally with L. intracellularis and S. enterica. At intervals of time fecal samples will be collected and the amount ofS. entericain each sample will be determined using a modified most probable number analysis tool. The results will be compared to pigs only challenged with S. enterica. In the second specific aim, we will use a vaccine used to protect pigs fromL. intracellularis and determine whether it protects pigs from S. enterica.</p><p> To do this work, pigs will be vaccinated and then challenged with one or both pathogens. Fecal samples will be collected as in the first specific aim and the amount of S. enterica in each sample determined using the most probable number tool. The results will be compared to non-vaccinated but challenged pigs.</p><p> In the third specific aim, the fecal samples collected in specific aims 1 and 2 will be evaluated to determine the compositions of their microbiomes. Microbiome analysis will used standard techniques that include extraction of total DNA from each fecal sample and using polymerase chain reaction to amplify the 16S rRNA genes in the samples. These PCR products will then be subjected to high yield next generation DNA sequencing. The DNA sequences will be used for taxonomic assignments using the Ribosomal DNA Project data base. Identification of enriched or depleted microbiomes will use MetaStats.</p>