Pathology of liver granulomas in turkeys

Liver granulomas from five- and seven-week-old turkeys were studied by light and electron microscopy and by bacterial culture. Granulomas of five-week-old poults were composed of a caseous, necrotic center surrounded by consecutive zones of heterophils, giant cells, macrophages, and finally by lymphocytes. Tissue Gram and modified Dieterle stains demonstrated numerous gram-positive, filamentous bacteria in necrotic centers with radial extension of the bacteria to the zone of giant cells. Electron microscopic examination revealed septate, filamentous bacteria within an electron-dense milieu between heterophils, macrophages, and giant cells. An anaerobic, gram-positive bacillus and a staphylococcus were isolated from most granulomas examined. In broth, the bacillus formed long filaments or chains morphologically similar to those in tissue sections. The bacillus was identified tentatively as Eubacterium tortuosum. The staphylococcus had cultural reactions typical for Staphylococcus epidermidis. Intravenous inoculation of three-week-old poults with a mixture of E. tortuosum and S. epidermidis produced granulomas in liver and spleen and multiple mucosal ulcers in the duodenum and colon.