The biopsy specimen from the sinus tract on the medial surface of the left foot showed a subcutaneous abscess of neutrophils, within which was a sulfur granule. A bacterial culture yielded gram-positive filamentous rods, identified by DNA sequencing as Nocardia otitidiscaviarum. A foot radiograph showed no evidence of bone invasion. Treatment with trimethoprim-sulfamethoxazole and minocycline was initiated, with remarkable clinical improvement of the infection observed at follow-up visits. By 12 months of therapy, the patient’s infection appeared to be resolved, so the antibiotic therapy was discontinued.
Chronic Foot Infection in a Mexican Immigrant—Diagnosis. Arch Dermatol. 2006;142(1):101-106. doi:10.1001/archderm.142.1.101-b