Actinobacillus actinomycetemcomitans isolated from a case of cutaneous botryomycosis.

Cutaneous botryomycosis is an uncommon chronic suppurative bacterial skin infection that can mimic a fungal infection both clinically and histopathologically. Causative bacteria, most commonly Staphylococcus aureus, aggregate to form characteristic granules. We report the case of a 52-year-old black man who developed cutaneous botryomycosis of the hand following trauma. Routine bacterial cultures grew S aureus and Actinobacillus actinomycetemcomitans, a fastidious gram-negative bacillus known to cause periodontal disease, endocarditis, and actinomycosislike soft tissue infections. Despite culture-proven eradication of S aureus with long-term appropriate antibiotic therapy, the lesion, resolved only after fluoroquinolone treatment directed against A. actinomycetemcomitans, suggesting that A. actinomycetemcomitans was of etiologic significance.