A Woman with Nodular Skin Lesions

Diagnosis: Myobacterium marinus deep cutaneous lesions. The differential diagnosis for this patient included sporotric hosis, nontuberculous mycobactnerial infection, extrapulmonary tuberculosis, fungal infection (e.g., blastomycosis), and nocardiosis [ 1, 2]. M. marinurm classically causes "swimming pool" or "fish tank" granulomas [3]. The lesions can present as cutaneous nodules (sporotrichoid), persistent ulcers, tendonitis, tenosynovitis, and, rarely, as deep or disseminated lesions [1, 2, 4-8]. This patient had exposures not only to a fish tank but also to gardening with roses, placing her at a significant risk for both M. marinum infection and sporotrichosis. The failure of the patient's lesions to respond to vanomycin (especiand itraconazole therapy increased the likelihood that a pathogen other than Staphylococcus aureus or Sporotrichium species was present. The diagnosis was finally established when a culture of a biopsy specimen grew M. marinum, whose identity was confirmed by the Tenessee Department of Health laboratory. There are no findings from controlled clinical trials to guide therapy for M. marinum infection, but recent reports support the use of clarithromycin (especially in combination therapy) Figure 2. Lesions on the patient's forearm that progressed despite administration of treatment for staphylococcal infection and sporotrichosis. Cultures yielded M. marinum.