Association between Salmonella sp. and Yersinia enterocolitica infection in swine

By: Erin Shaw

Michigan State University, Class of 2013

Shaw, Erin; Funk, Julie; Plovanich-Jones, Anne E.; College of Veterinary Medicine, Michigan State University, East Lansing, MI 48824

Swine are known reservoirs for both Salmonella and Yersinia enterocolitica. Both are foodborne pathogens and can result in zoonotic disease if contamination of pork products occurs during harvest.  The epidemiology of Y. enterocolitica and Salmonella in swine is not well understood, and cost-effective preharvest control measures have not been identified. Previous reports from experimental studies in mice suggest that, via quorum-sensing, Salmonella detects Y. enterocolitica signals, increasing Salmonella colonization (Dyszel et al, 2009). This may present an opportunity for preharvest control via targeting Y. enterocolitica infection or disruption of quorum sensing. Demonstration of this association in naturally infected swine has not been demonstrated.

The objective of this study is to determine if there is an association between fecal shedding of Salmonella and Y. enterocolitica in naturally infected swine. DNA was extracted from 1232 fecal samples collected from finishing pigs at commercial farms. The Salmonella status of the samples was known from previous culture results. All Salmonella positive samples and a random selection of negative samples were included in the study. High throughput duplex real-time PCR was conducted to detect the presence or absence of Y. enterocolitica.

TaqMan® assays targeted the Y. enterocolitica ail gene and a Y. enterocolitica specific region of the 16S rRNA gene. The prevalence rate of Y. enterocolitica in Salmonella positive versus Salmonella negative fecal samples was 3.9% and 7.5%, respectively. Based on cross-sectional sampling, and the status of an individual fecal sample, Salmonella positive pigs were less likely to be Y. enterocolitica positive.

Student Support: Large Animal Clinical Sciences Department, College of Veterinary Medicine, Michigan State University

Research Support: NIH Grant T35RR017491 to MSU