Localization of viable bacteria and bacterial antigens in arthritic joints of Erysipelothrix rhusiopathiae-infected pigs.

Chronic polyarthritis was induced in pigs by infection with Erysipelothrix rhusiopathiae (serovar 2, strain T28). Viable bacteria could be reisolated as long as 5 months post-infection from synovial fluid, synovial tissue and from isolated chondrocytes. The number of viable bacteria could be increased by hypotonic shock of the chondrocytes indicating a substantial intracellular amount of bacteria. Bacterial antigens were shown by immunohistochemistry to be present on the surface of both chondrocytes and synovial cells in arthritic joints. Neither viable bacteria nor bacterial antigen were detected in unaffected joints.