Ulcerative cutaneous mycobacteriosis due to Mycobacterium ulcerans: report of two Mexican cases.

We report two patients from Central Mexico, with ulcerated cutaneous lesions containing acid-fast bacilli (AFB) and ultimately diagnosed as Mycobacterium ulcerans disease. The first patient had a long history (11 years) of disease involving multiple lesions of both upper and lower extremities. Histopathological changes included necrosis of the subcutaneous tissue with large numbers of extracellular AFB. Cultures at 32 degrees C were "positive for mycobacteria," but were not further identified. The polymerase chain reaction for M. ulcerans performed on skin bopsies was positive. The lesions improved after treatment with rifampin and isoniazid (INH) for one month, followed by ethambutol and streptomycin. The second case followed trauma to the right hand, which spread over 2 years to the right upper extremity, the back, and both legs, with a loss of digits and metacarpal bones of the right hand. The histopathological findings were similar to the first case, including presence of AFB. PCR for M. ulcerans on extracts of skin biopsies was positive. Rifampin, INH, pyrazinamide, and levofloxacin resulted in marked improvement of the ulcer; ethambutol and streptomycin were later used, also. We report these cases because they are rare (approximately 6 previous cases were reported from Mexico), and both are unusually disseminated. They are significant in alerting the medical community to M. ulcerans infection, which is still active in Mexico, and the treatment used has not been reported previously.