|CURTISS III, R|
Submitted to: ARS Food Safety and Inspection Service Research Workshop
Publication Type: Abstract Only
Publication Acceptance Date: 12/13/1995
Publication Date: N/A
Technical Abstract: Previously we have demonstrated reduced colonization of wild-type Salmonella typhimurium in swine following vaccination with deltacyadeltacrp deletion mutant. Additional strains were constructed with the following mutations: pmi, deltacyadeltacrp pmi, deltacyadeltacrp/pSTV1, phoP, and deltaaroA. Pigs were grouped (n=6), housed by individual strain, and challenged perorally with 10**9 CFU wild-type or one of the mutants. Clinical signs were monitored, rate of gain was measured, and swabs were collected for bacteriology. Pigs were necropsied at 1, 2, and 3 weeks postchallenge and tissues were collected for bacteriology. Pigs challenged with the deltacyadeltacrp pmi or phoP mutants were least affected clinically while pigs challenged with the deltacyadeltacrp pmi mutant had the least weight loss. Most numbers of positive tissues were recovered from pigs challenged with wild-type (75%) followed by pmi (67%), phoP (54%), deltacyadeltacrp/pSTV1 (38%), deltacyadeltacrp pmi (32%), and deltaaroA (32%) mutants. No gross delayed type hypersensitivity response was observed for any group. Quantitative bacteriology varied between groups with the highest numbers of Salmonella recovered from the tonsil and ileocolic lymph nodes. These data provide criteria necessary for selection of suitable vaccine candidates.