Submitted to: American Society for Microbiology
Publication Type: Abstract Only
Publication Acceptance Date: February 28, 2011
Publication Date: July 18, 2011
Citation: Bearson, B.L., Bearson, S.M. 2011. An attenuated Salmonella enterica serovar Typhimurium strain reduces disease severity, fecal shedding, and gastrointestinal colonization in swine due to virulent S. Typhimurium challenge [abstract]. In: Abstracts of the 111th General Meeting of the American Society for Microbiology, May 21-24, 2011, New Orleans, Louisana. p. 179. Technical Abstract: Background: Salmonella serovars frequently colonize swine without causing overt disease. Pathogen interventions are needed to limit Salmonella colonization in swine. Vaccination with an attenuated Salmonella strain may reduce pathogen carriage in swine and enhance food safety. Methods: Swine study 1: S. Typhimurium mutant BBS 202 was constructed and tested for attenuation in swine. Two groups (n=5/group) of 6-week old piglets received an intranasal inoculation of either BBS 202 or wild-type S. Typhimurium and were monitored for clinical disease symptoms and pathogen fecal shedding. Swine study 2: To determine whether the attenuated BBS 202 strain could provide protection against S. Typhimurium challenge, 2 groups of 14 piglets received an intranasal inoculation of BBS 202 or a placebo of PBS at 6-weeks of age with a booster 2-weeks later. All pigs were challenged with wild-type S. Typhimurium by intranasal inoculation at 11-weeks of age and monitored for clinical disease symptoms, fecal shedding of S. Typhimurium and pathogen colonization of gastrointestinal tissues. Results: The average swine rectal temperature (fever) and swine fecal shedding of S. Typhimurium was significantly decreased in pigs inoculated with BBS 202 compared to pigs that received the wild-type strain, indicating that BBS 202 was attenuated for virulence in swine. In the vaccination study, the average swine rectal temperature (fever), fecal shedding of wild-type S. Typhimurium, and S. Typhimurium colonization of gastrointestinal tissues (Peyer’s patches and ileocecal lymph nodes) were significantly decreased following wild-type S. Typhimurium challenge of BBS 202 vaccinated pigs compared to mock-vaccinated pigs. Conclusions: Vaccination of pigs with S. Typhimurium BBS 202 reduced disease severity, pathogen fecal shedding, and gastrointestinal colonization following challenge with virulent S. Typhimurium compared to mock-vaccinated pigs.