Stress induced <it>Salmonella </it>Typhimurium recrudescence in pigs coincides with cortisol induced increased intracellular proliferation in macrophages

<p>Abstract</p> <p><it>Salmonella </it>Typhimurium infections in pigs often result in the development of carriers that intermittently excrete <it>Salmonella </it>in very low numbers. During periods of stress, for example transport to the slaughterhouse, recr...

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Bibliographic Details
Main Authors: Verbrugghe Elin, Boyen Filip, Van Parys Alexander, Van Deun Kim, Croubels Siska, Thompson Arthur, Shearer Neil, Leyman Bregje, Haesebrouck Freddy, Pasmans Frank
Format: Article
Language:English
Published: BMC 2011-12-01
Series:Veterinary Research
Online Access:http://www.veterinaryresearch.org/content/42/1/118
Description
Summary:<p>Abstract</p> <p><it>Salmonella </it>Typhimurium infections in pigs often result in the development of carriers that intermittently excrete <it>Salmonella </it>in very low numbers. During periods of stress, for example transport to the slaughterhouse, recrudescence of <it>Salmonella </it>may occur, but the mechanism of this stress related recrudescence is poorly understood. Therefore, the aim of the present study was to determine the role of the stress hormone cortisol in <it>Salmonella </it>recrudescence by pigs. We showed that a 24 h feed withdrawal increases the intestinal <it>Salmonella </it>Typhimurium load in pigs, which is correlated with increased serum cortisol levels. A second in vivo trial demonstrated that stress related recrudescence of <it>Salmonella </it>Typhimurium in pigs can be induced by intramuscular injection of dexamethasone. Furthermore, we found that cortisol, but not epinephrine, norepinephrine and dopamine, promotes intracellular proliferation of <it>Salmonella </it>Typhimurium in primary porcine alveolar macrophages, but not in intestinal epithelial cells and a transformed cell line of porcine alveolar macrophages. A microarray based transcriptomic analysis revealed that cortisol did not directly affect the growth or the gene expression or <it>Salmonella </it>Typhimurium in a rich medium, which implies that the enhanced intracellular proliferation of the bacterium is probably caused by an indirect effect through the cell. These results highlight the role of cortisol in the recrudescence of <it>Salmonella </it>Typhimurium by pigs and they provide new evidence for the role of microbial endocrinology in host-pathogen interactions.</p>
ISSN:0928-4249
1297-9716