Mycobacterium marinum infections in transplant recipients: case report and review of the literature.

Infections due to Mycobacterium marinum are rarely encountered following organ and tissue transplantation. Herein, we report a case of M. marinum infection in a kidney and pancreas transplant recipient who manifested clinically with multiple locally spreading sporotrichoid-like cutaneous nodules in his left forearm. In order to provide a general overview of post-transplant M. marinum infections, we reviewed and summarized all previously reported cases of this infection that occurred after transplantation. Including our index case, all 6 cases presented with multiple cutaneous and subcutaneous nodules that had spread locally in the involved extremity. One patient had lesions located in non-contiguous body sites suggesting either systemic dissemination or multiple sites of inoculation. In all but 1 patient, the cutaneous nodules appeared in an ascending pattern and following exposure to fish tanks or after contact with the marine environment. The diagnosis of M. marinum infection was suspected on clinical grounds and confirmed by mycobacterial culture. Treatment consisted of at least 2 active antibiotics (such as rifamycins, ethambutol, tetracyclines, or macrolides) for 4-9 months, resulting in clinical cure or improvement. Relapse was observed in 1 patient despite completing 6 months of antibiotic therapy. One patient had surgical excision of the lesions. In conclusion, M. marinum should be considered as the cause of cutaneous and subcutaneous nodules in transplant recipients, particularly in the context of fish tank or marine exposure. Compared with the immunocompetent hosts, M. marinum infection may have a more aggressive clinical course after transplantation, and may require a longer duration of antibiotic treatment. Early diagnosis and treatment may prevent local spread and potential systemic dissemination.