Anaerobic osteomyelitis.

Abstract

Anaerobic bacteria were isolated from deep specimens obtained during surgical debridement for osteomyelitis in 40 of 182 patients treated over a 28 mo. period. Mixtures of aerobes and anaerobes were cultured from 31 patients, but the pathogenic role of the anaerobes was uncertain. In the other 9 patients, only anaerobes were isolated, confirming the pathogenic nature of the organisms. Treatment failed in 61.5% of the 31 patients with mixed aerobic-anaerobic infections. This failure rate was 3 times the rate for treatment of aerobic osteomyelitis, suggesting that the anaerobes may have played a role in these mixed infections. Generally, the patients with mixed aerobic-anaerobic infections were younger (mean age, 39.5 yr) and the interval between the onset of symptoms and the isolation of anaerobes was prolonged (mean interval, 6.2 yr); 21 had sustained a traumatic injury and 11 of the 21 had had massive soft-tissue damage. The 9 patients with pure anaerobic osteomyelitis responded to surgical and antimicrobial therapy without recurrent sepsis. Compared with the patients who had mixed infection, these patients were older (mean age, 54.2 yr) and the duration of their symptoms prior to the recovery of anaerobic isolates was shorter (.ltoreq. 1 mo. in 7 patients). The infection was associated with a metallic foreign body in 7 of these patients. The incidence of anaerobic osteomyelitis observed in this study was much higher than what was previously reported. Routine culture of surgical specimens of tissue for anaerobic organisms and improved anaerobic laboratory methods are probably responsible. Because anaerobes play an important role in osteomyelitis, tissue specimens from all osteomyelitis patients should be cultured anaerobically.