Submitted to: Food Safety Consortium Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 9/22/2004
Publication Date: 10/3/2005
Citation: Huff, G.R., Huff, W.E., Johnson, M.G., Nannapenini, R. 2005. Update: Stress-induced chronic infections of turkeys with Listeria monocytogenes and implications for product and processing plant contamination. In: Proceedings of the Food Safety Consortium, October 3-5, 2004, Ames, Iowa. 2004 CDROM. Interpretive Summary:
Technical Abstract: In experiment 1, turkeys were challenged with Lm ScottA at day of age. The survivors of this challenge were immunosuppressed with DEX at 4 weeks of age. Body weights were decreased (P = 0.0001) and airsacculitis scores were increased (P = 0.0005) by challenge with Lm and birds challenged at day of age had significantly higher incidence of lameness at necropsy (P=0.0004). Significant changes were observed in the relative weights of liver, bursa, and spleen of Lm challenged birds. However, Lm was not isolated from any of the synovial tissue swabs or organs of challenged birds. In experiment 2, control turkeys and turkeys immunosuppressed with DEX were challenged at 5 weeks by air sac inoculation of 10E6 cfu Lm ScottA. Lm challenge decreased body weight (P=0.04) and the relative weight of the bursa of Fabricius (P = 0.02) and increased the relative liver weight (P= 0.04). An arthritic condition characterized by enlarged, thickened, and distended joint capsules was significantly higher in Lm challenged birds however, Lm has not been isolated from these tissues. These studies suggest that Lm may have chronic affects on turkeys, including decreased body weight, changes in organ weights and detrimental effects on leg health, however using available methods we have not been able to isolate Lm from these chronically affected birds. We have previously reported that culture-negative synovial tissue swabs from turkeys challenged with Lm ScottA that formed biofilms after extended incubation were positive for Lm using fluorescent antibody staining of challenged avian macrophage cell lines. However, using two different PCR procedures, we have been unable to detect Lm in these samples. Preliminary studies of the propensity of joint isolates from turkeys challenged at one day of age suggests that they are able to form more dense biofilms than laboratory strains under certain test conditions.