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item LY, M
item Cray, Paula
item Ladely, Scott
item FANG, F
item LIBBY, S

Submitted to: American Society for Microbiology Meeting
Publication Type: Abstract Only
Publication Acceptance Date: 4/30/1999
Publication Date: N/A
Citation: Ly, M., Galiano, C., Cray, P.J., Ladely, S.R., Testerman, T., Fang, F., Libby, S.J. 1999. Analysis of defined mutants of salmonella choleraesuis in swine. American Society for Microbiology Meeting. Session No. 233/B/D. Abstract B/D-323. P. 93.

Interpretive Summary:

Technical Abstract: Salmonella choleraesuis is a swine-adapted serotype of Salmonella that can cause severe systemic infection in weaned animals and chronic asymptomatic carriage in older animals. Carrier animals represent a source of herd infection and potential human infection from contaminated meat products. Understanding the virulence of S. choleraesuis in the natural host will help lead to the production of live, attenuated vaccines. We have constructed defined mutations in the slyA, rpoE, and spvR genes of virulent strain of S. choleraesuis and used mutants to infect weaned pigs. Virulence of these mutants was determined by measuring the amount of fecal, nasal, and tonsillar shedding, body temperature, severity of diarrhea, and level of tissue colonization at necropsy as compared to pigs infected with the wild type parent. Swine infected with these mutants did not show clinical symptoms of salmonellosis, as did pigs infected with the wild type parent. The level of tissue colonization differed among all the mutants, but all mutants were able to infect deep tissues, slyA and rpoE mutants were used to vaccinate weaned swine. After four weeks, vaccinated and unvaccinated pigs were challenged with the wild type parent. Vaccinated pigs did not develop clinical symptoms following challenge (2/16) whereas unvaccinated pigs developed diarrhea and fever, had greater level of tissue infection, and shed the challenge strain persistently (16/16). Animals produced a significant specific immune response following challenge. These results show that swine can be protected from virulent S. choleraesuis by live attenuated slyA and rpoE mutants of S. choleraesuis.