Septic arthritis caused by Bacteroides fragilis.

As improvements in bacteriologic techniques have enhanced the recovery of anaerobic bacteria from clinical specimens, there has been an increasing awareness of the role of anaerobes in disease. Bacteroides fragilis is the most common anaerobic organism found in clinical specimens. Although it is the anaerobe most frequently associated with bacteremia and a common isolate in intraabdominal infections, infections of the female genital tract, wounds, and abscesses, B. fragilis is a rare cause of septic arthritis. The isolation of this organism from four patients with septic arthritis in three Cleveland hospitals between 1978 and 1982 suggests that septic arthritis due to B. fragilis may be a more common clinical entity than previously appreciated. In this report we describe these cases and review the pertinent literature.