[Mycobacterium ulcerans cutaneous infections: Buruli ulcers]

Mycobacterium ulcerans skin infection or Buruli ulcers are common in children in many rural tropical areas. The usual clinical appearance is a deep, rapidly developing chronic ulcer associated with necrosis of subcutaneous fat. Patients are usually seen at an advanced stage. Bacteriologic identification is not always possible because the pathogen, Mycobacterium ulcerans, is an atypical mycobacteria that is difficult to isolate and grows slowly in culture. Medium although of little assistance in tropical regions, the histological features are highly characteristic and can allow diagnosis in areas in which the disease is rare and unsuspected. The pathogenic effects of Mycobacterium ulcerans are due to the production of a necrotizing exotoxin with an immunosuppressive action. Treatment using antituberculosis and antileprosy drugs has been disappointing. Surgery is usually required and causes extensive sequels in many cases, the best technique being an excision/graft procedure. Many epidemiologic characteristics of Buruli ulcers which are andemic in regions with and aquatic ecosystem are still unclear including the mode of infection, transmission and reservoir. Recent outbreaks, particularly in west Africa, may be related to changes in the natural environment.