Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: August 5, 2013
Publication Date: October 5, 2013
Citation: Bearson, B.L., Bearson, S.M., Lee, I.S., Kich, J. 2013. A live attenuated Salmonella enterica serovar Typhimurium vaccine provides cross-protection against Salmonella serovars to reduce disease severity and pathogen transmission. Final Program and Abstracts of the 4th ASM Conference on Salmaonella. p. 50. Technical Abstract: A live attenuated Salmonella enterica serovar Typhimurium vaccine was developed to confer broad protection against multiple Salmonella serovars to prevent disease and reduce pathogen colonization and shedding. Two vaccine trials were performed in swine to determine the protection afforded by the vaccine to challenge with two distinct Salmonella serovars. In the first vaccine trial, 3-4 week old pigs were administered two doses of the vaccine (vaccination and booster) and challenged with wild-type S. Typhimurium UK1 that causes gastroenteritis. The swine rectal temperatures and plasma IFN' levels, which are indications of disease severity, were significantly reduced in vaccinated pigs at days 1, 2, and 3 post-challenge (p.c.) compared to mock-vaccinated swine. Fecal shedding of wild-type S. Typhimurium UK1 was significantly reduced at days 2, 3, and 7 p.c. in vaccinated pigs compared to mock-vaccinated swine. Furthermore, tissue colonization of the cecum, ileocecal lymph nodes, and Peyer’s patches in the distal ileum at day 7 p.c. was significantly reduced in vaccinated swine. In the second vaccine trial, pigs were administered a single dose of the vaccine and challenged with a virulent S. Choleraesuis that causes systemic disease in swine. Compared to the mock-vaccinated group, the vaccinated pigs exhibited significantly reduced rectal temperature at days 1, 3, and 7 p.c.; serum IFN' levels at days 3 and 7 p.c.; and tissue colonization of the liver, spleen, ileal Peyer’s patches, ileocecal lymph nodes, cecum, and tonsils at day 7 p.c. Furthermore, during the 7-day challenge period, S. Choleraesuis isolation from blood cultures was significantly more frequent in mock-vaccinated pigs compared to vaccinated swine, and the total number of pigs that were blood culture-positive at any time during the trial was significantly higher in the mock-vaccinated group. The data from these two vaccine trials indicate that the live attenuated S. Typhimurium vaccine can both protect swine from Salmonella that cause systemic disease in pigs and also reduce the potential for transmission of Salmonella that cause foodborne disease in humans. Therefore, this dual-use Salmonella vaccine is intended to not only protect the health status of the swine herd to reduce production losses, but also support food safety and public health by reducing the spread of human foodborne Salmonella from pen to plate.