Prepatellar bursitis due to Brucella abortus: case report and analysis of the local immune response

A case of prepatellar bursitis in a man with chronic brucellosis is presented. Brucella abortus biotype 1 was isolated from the abundant yellowish fluid obtained from the bursa. Clinical and epidemiological data did not suggest a direct inoculation of the agent in the bursa. However, the patient mentioned occasional local trauma due to recreational sports, which may have constituted a predisposing factor. As determined by ELISA, there were higher levels of IgG against Brucella LPS and cytosolic proteins detected in the patient's bursal synovial fluid when compared with serum. Levels of proinflammatory cytokines (tumour necrosis factor alpha, interleukin 1 beta, gamma interferon, interleukin 8 and MCP-1) were higher than in synovial fluids obtained from patients with rheumatoid arthritis and a patient with septic arthritis, and a zymographic analysis revealed a gelatinase of about 92 kDa. These findings indicate that it may be possible to diagnose brucellar bursitis by measuring specific antibodies in the bursal synovial fluid. In addition, our findings suggest a role of increased local levels of proinflammatory cytokines and gelatinases in the inflammatory manifestations of brucellar bursitis.