Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 11/15/2006
Publication Date: N/A
Technical Abstract: The objective of this study was to determine if Listeria monocytogenes (Lm) infection of stressed turkey poults would result in colonization of synovial tissues. Male turkey poults, housed in floor pens, were subjected to cold stress from d 4 through 12 and were exposed to an aerosol challenge of either the Scott A strain of Lm, Escherichia coli (Ec), or the combination (Lm+Ec). All challenged birds were housed in the same building, while non-challenged controls were housed in a separate, biosecure building. At seven wks, poults were given an immunosuppressive dose of dexamethasone (Dex) and the same bacterial challenges were added to their drinking water. One wk post-challenge 4-6 birds per group were weighed, necropsied, and knee synovial tissues were cultured for Lm using pre-enrichment in University of Vermont medium (UVM) and Fraser broth, isolation of Lm on Listeria selective agar plates, and confirmation using biochemical tests. LM was isolated from knee synovial tissue of 75% of cold stressed poults challenged with Dex+Ec+Lm, 43% of cold-stressed poults challenged with Dex+Ec alone, and 20% of cold stressed poults challenged with Dex+Lm alone. Lm was not isolated from non-cold stressed birds challenged with either Dex+Lm or Dex+Ec+Lm, but was isolated from 25% of non-cold stressed birds challenged with Dex+Ec. Lm was not isolated from synovial tissues of any of the non-challenged controls. There were no differences in body weight due to early cold stress, however Dex treatment itself and Dex + all bacterial challenges significantly decreased body weight at 8 wks. These data suggest that Lm colonization of turkey synovial tissue can be enhanced by early cold stress and by concurrent infection of Dex-treated poults with Ec.