Mycobacterium marinum infection in a renal transplant recipient

Background. Infections with atypical mycobacteria occur more frequently in patients with solid organ transplants than in the normal host. Methods. We report a case of cutaneous Mycobacterium marinum infection in a renal transplant recipient. The patient presented with nodules on the forearm after returning from a fishing trip and was treated for cellulitis without success. Results. Cultures of a biopsy of the lesion grew M. marinum. The patient was treated with ethambutol and ciprofloxacin with a good response; however, 9 months of treatment were required for complete resolution. Conclusion. Immunosuppressive therapy for renal transplantation increases susceptibility to a variety of opportunistic infections. A patient who presents with nodules on the extremities should be questioned regarding contact with fish, aquatic environments, or fish tank water, in which case infection with M. marinum should be considered. The diagnosis and treatment of this infection in transplant recipients is discussed.