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Develop a model system for colonization of turkey synovial tissues and bones with Listeria monocytogenes utilizing stress-induced immunosuppression. Develop an assay for detection of biofilm communities of Listeria monocytogenes in the synovial tissues of turkeys. Determine and compare the propensity of joint isolates, environmental isolates, and challenge cultures to form biofilm communities and to colonize stainless surfaces in vitro.
A series of experiments will determine optimum route of infection and dosage for colonization of synovium and bone with L. monocytogenes. In each experiment, 5- wk-old birds will be weighed, and half will be treated with 3 injections into the thigh muscle of 2mg/kg DEX on alternating days. On the day of the 3rd DEX injection half of the DEX-treated birds will be challenged with either air sac or intra peritoneal inoculation or oral gavage of either 102 or 104 cfu of a virulent strain of L. monocytogenes. Mortality will be monitored twice daily after challenge. All dead birds will be weighed and scored for lesions characteristic of listeriosis, especially heart abnormalities, for lesions of airsacculitis and for TOC lesions. Livers, spleens, bursae, and hearts will be weighed. Three days after challenge, 4 birds/pen will be bled. Clinical chemistry analysis of serum levels of total protein, albumin, glucose, triglycerides, cholesterol, uric acid, calcium, magnesium, phosphorus, and iron, and the enzyme activities of alkaline phosphatase (AP), alanine aminotransferase (ALT), aspartate aminotransferase (AST), and creatine kinase (CK) will be performed using a Ciba-Corning automated clinical chemistry analyzer in order to confirm stress and infection related physiological changes. Two weeks post-challenge all remaining birds will be necropsied and cultured as described for mortalities.