Submitted to: Salmonella and Salmonellosis International Symposium
Publication Type: Abstract only
Publication Acceptance Date: 7/25/1997
Publication Date: N/A
Citation: Interpretive Summary:
Technical Abstract: Salmonella choleraesuis (SC) is a host adaptive pathogen of economic importance to the swine industry. In order to establish a model for experimental infection, we orally challenged newly weaned pigs (10 pigs per group) with 3 levels of SC. The challenge strain used was resistant to both nalidixic acid and novobiocin. Seven days post challenge, all pigs were necropsied and tonsils, ileocolic lymph nodes, and cecal contents were collected. Tissue samples and cecal contents were enriched for Salmonella. Colonies recovered on Brilliant Green Agar containing nalidixic acid and novobiocin were examined for typical Salmonella type morphology; suspect colonies were tested further with Salmonella O Antiserum. A dose dependent relationship was observed with SC being cultured from tissues of 1, 4, and 10 of the pigs challenged with 10**4, 10**6, and 10**8 CFU, respectively. Shedding SC, as determined by daily culture of rectal swabs, was also increased when pigs were dosed with 10**4, 10**6, and 10**8 CFU as the percentages of pigs culturing positive were 0, 10, and 70%, respectively. Likewise, the percentages of pigs exhibiting a temperature of more than 103.6oC at some time post challenge were 10, 20, and 50% for those dosed with 10**4, 10**6, and 10**8 CFU SC, respectively. These data indicate that the optimal oral dose of SC is greater than 10**6 CFU.