Culture of per-wound bone specimens: a simplified approach for the medical management of diabetic foot osteomyelitis

Abstract

Surgical percutaneous bone biopsy specimen after a 14-day antibiotic-free period represents the gold standard of care for diabetic foot osteomyelitis but may be difficult to implement in many institutions. We evaluate a simplified strategy based on the results of per-wound bone specimen culture. For that purpose, we retrospectively reviewed the charts of 80 consecutive patients with diabetic osteomyelitis and bone sample obtained via the wound after a careful debridement. The outcome was defined as favourable if there was a complete healing of the wound with no sign of infection and stable or improved bone X-ray 6 months after antibiotic therapy completion. Culture of bone specimens was positive in 96% of patients, although half of the patients did receive a course of antimicrobials within 14 days of the bone specimen being obtained. A total of 129 bacterial isolates were obtained from bone cultures with a mean of 1.6 ± 1 isolates per patient (Staphylococcus aureus: 33%; central nervous system: 14%; streptococci: 9%; enterococci: 12%; corynebacteria: 4%; Gram-negative bacilli: 20%; anaerobes: 4%). Forty-six percent of cultures were monomicrobial. The mean duration of follow-up from diagnosis was 17 ± 1 months. Six months after discontinuation of antibiotic, six patients (7.5%) had died, nine were considered as therapeutic failures and 65 were considered as cured. Fifty-four of these 65 patients had follow-up data available at 1 year and remained in remission. In conclusion, a simplified procedure based on the culture of bone sample obtained via the ulcer after a careful debridement of the wound is effective in the medical management of diabetic foot osteomyelitis.