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United States Department of Agriculture

Agricultural Research Service

Title: Effect of 2-Deoxy-D-Glucose Induced Stress on Salmonella Choleraesuis Shedding and Persistence in Swine

Authors
item Stabel, Thomas
item Cray, Paula

Submitted to: Research in Veterinary Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: December 3, 2003
Publication Date: June 20, 2004
Citation: Stabel, T.J., Cray, P.J. 2004. Effect of 2-deoxy-d-glucose induced stress on Salmonella choleraesuis shedding and persistence in swine. Research in Veterinary Science. 76(3):187-194.

Interpretive Summary: Salmonella species of bacteria are a serious worldwide problem causing swine disease estimated to cost $100 million annually in the United States. Salmonella bacteria also are important human pathogens and are of great concern in food safety. The production and marketing of pigs presents a number of stressful situations that can lead to production losses and disease. Central to the study of porcine stress and its role in salmonellosis and other diseases is the need to understand the potential interaction between stress and fecal shedding of bacteria. Pigs were inoculated intranasally with S. choleraesuis. Pigs were then injected at different times with 2- deoxy-D-glucose (2DG) and dexamethasone (Dex), compounds previously shown in pigs to cause stress and/or immune suppression. Regimens of 2DG and Dex did not cause renewed fecal shedding of Salmonella even when tissues were culture positive for Salmonella. Persistent shedding was not affected by 2DG administration alone; however, the combination of 2DG and Dex administration caused a 20-fold increase in Salmonella fecal shedding. In conclusion, a new paradigm is proposed to accurately describe the Salmonella carrier-state in swine. Carriers should be divided into two subgroups: (a) Salmonella carriers unaffected by stress (and do not shed Salmonella in the feces), and (b) persistent shedders, influenced by stress, that cycle between an active and inactive state of fecal shedding. Eventual beneficiaries of this information are the American consumer since new intervention strategies for salmonellosis will allow a continued supply of inexpensive, wholesome pork and pork products.

Technical Abstract: The objective of this study was to determine the effect of 2-deoxy-D- glucose (2DG) and dexamethasone (Dex) on the Salmonella choleraesuis carrier-state in swine. Salmonella-free male and female mixed-breed pigs (n = 29) were allotted to 4 groups. On day 0, two challenge groups were inoculated intranasally with 1 x 10**6 S. choleraesuis and two control groups received saline. At 6 weeks post inoculation (PI), one challenge group (n = 8) and one control group (n = 8) each received a single subcutaneous injection of 2DG and the other challenge (n = 7) and control group (n = 6) received saline. Finally, at 7 days post-2DG-administration, 2DG-treated animals received Dex injections and non-treated pigs received saline. Throughout the study, individual fecal loops were collected and quantitatively cultured for Salmonella; tonsil and nasal swabs were qualitatively cultured. Pigs were necropsied 18 days after 2DG treatment (7 days after the last Dex injection). Results indicated that regimens of 2DG and Dex did not cause recrudescence of Salmonella fecal shedding even when tissues were culture positive for Salmonella. Persistent shedding was not affected by 2DG administration; however, Dex administration caused a 20-fold increase in Salmonella fecal shedding. In conclusion, a new paradigm is proposed to accurately describe the Salmonella carrier-state in swine. Carriers should be divided into two subgroups: (a) Salmonella carriers unaffected by stress (and do not shed Salmonella in the feces), and (b) persistent shedders, influenced by stress, that cycle between an active and inactive state of fecal shedding.

Last Modified: 11/23/2014
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