Title: Culture of percutaneous bone biopsy specimens for diagnosis of diabetic foot osteomyelitis: concordance with ulcer swab cultures
Authors: Senneville E, Melliez H, Beltrand E, Legout L, Valette M, Cazaubiel M, Cordonnier M, Caillaux M, Yazdanpanah Y, Mouton Y
Source: Clin Infect Dis 2006 Jan 1;42(1):57-62.
PODIATRIC RELEVANCE:
Effective management of lower extremity infections depends upon a quick and correct diagnosis of osteomyelitis as well as proper identification of the causative organisms. In light of the increasing incidence of bacterial resistance it is even more important than ever to obtain accurate cultures to guide long term antibiotic therapy. This retrospective study was undertaken in attempt to determine if any concordance exists between cultured osteomyelitic pathogens, obtained via bone biopsy, and those pathogens cultured from wound swabs of the same diabetic feet.
METHODS:
A retrospective analysis was done on 76 patients with 81 incidence of foot osteomyelitis diagnosed by bacterial cultures after percutaneous bone biopsy. All patients had not received any antibiotics for at least 4 weeks prior to biopsy. Further narrowing of the population to those who had a cutaneous wound swab performed within 3 days prior to bone biopsy resulted in 69 patients. Cutaneous wound swab cultures were compared to those of the bone biopsies in the same patients, examining any concordance between the two methods.
RESULTS:
Of the 81 episodes of osteomyelitis, bone isolates were predominately Staphylococcus species (52%), and gram-negative bacilli (18.4%). Distributions in bone and ulcer were similar with the exception of coag-negative staphylococcus which had a predilection for bone.
Of the 69 patients who also underwent prior ulcer swabs, there was exact pathogen to pathogen concordance between wound swab and bone biopsy specimens in 12 (17.4%) of the 69 patients. In 21 patients (30.4%), the offending bone pathogen was isolated, although not exclusively, from the ulcer swab cultures. Individual pathogen specific concordance was 42.8% for Staphylococcus aureus, 28.5% for gram-negative bacilli, 25.8% for streptococci species. Overall concordance was 22.5% for all isolates.
1 Patient experienced an acute Charcot even 4 weeks after the percutaneous bone biopsy.
COMMENTS:
The authors conclude from the data that superficial swab cultures do not reliably identify bacteria causing osteomyelitis, and that percutaneous bone biopsy seems to be safe for patients with diabetic foot osteomyelitis. This evidence suggests that when considering long term antibiotics for likely osteomyelitis without prior debridement or amputation, a bone biopsy is still the gold standard and most effective way to discover the infecting pathogens. Would cultures do not effectively identify the pathogenic source of osteomyelitis.
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Disclaimer:
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