Submitted to: International Symposium on the Epidemiology and Control of Foodborne Pathogens in Pork
Publication Type: Proceedings
Publication Acceptance Date: 10/1/2003
Publication Date: 10/1/2003
Citation: GRIFFITH, R.W., HURD, H.S., LEVIS, I., MCKEAN, J.D. PERACUTE INFECTION OF SWINE WITH SALMONELLA. Proceedings of the International Symposium on the Epidemiology and Control of Foodborne Pathogens in Pork. 2003. p. 321-322.
Technical Abstract: It has recently been experimentally demonstrated that pigs exposed naturally to Salmonella on the floor of abattoir holding pens can become infected between two and six hours after being placed in the pens. In addition, we have demonstrated that tonsillar tissues are almost immediately culture positive following such exposure under experimental conditions. The objective of this study was to determine the shortest amount of time necessary for infection of selected tissues and to determine if the tonsil served as a route for Salmonella entry into lymphoid tissues. Forty-four Salmonella negative, market age swine (90 to 110 kg) were fasted overnight and exposed to approximately 2 X 10**6 Salmonella enterica serotype Typhimurium strain Chi 4232 (nalidixic acid resistant). The bacteria were mixed with a fecal slurry and the slurry spread on the floor of the pens. Pigs were euthanized at 15, 30, 45, 60, and 120 minutes following initial exposure. Tonsils of the soft palate, medial retropharyngeal lymph node, ileocecal lymph node, a five-centimeter section of the terminal ileum, cecal contents and 100 ml of blood were cultured by standard enrichment methods for Salmonella. Strain Chi 4232 was isolated from 98% (43/44) of tonsils. Strain Chi 4232 was isolated from the ileocecal lymph node within 45 minutes (2/9 pigs), terminal ileum within 15 minutes (1/9 pigs), cecal contents within 30 minutes (2/9 pigs), and blood within 45 minutes (1/9 pigs) following exposure. Strain Chi 4232 was not recovered from the medial retropharyngeal lymph node, indicating that the organism did not move rapidly into this node from the tonsil of the soft palate. Results of this study indicate that in less than the normal two-hour abattoir holding time, Salmonella can be recovered from selected sites in the pig.