Cutaneous Mycobacterium chelonae infection following repeated corticosteroid therapy

An 88-year-old woman, after repeated short corticosteroid therapies, presented chronic wounds on her left calf, formed of subcutaneous nodes progressing to fistula with serous discharge. The diagnosis of Mycobacterium chelonae cutaneous infection was settled with skin biopsies, after eliminating all differential diagnoses such as autoimmunity. This patient has been treated during seven months with two antibiotics and is actually in complete remission. Mycobacterium chelonae is a rapidly-growing non-tuberculous mycobacterium. The true prevalence is unknown but seems to be increasing. The mycobacterium causes mostly bone, cutaneous and soft tissues infections, frequently associated with subcutaneous injections or tap water exposed wounds. Disseminated infections has been reported in immunosuppressed patients. To prevent those infections, it is recommended to avoid contact between tap water and chronic wounds, sterile catheters, endoscopy or surgical equipment. Because of a lack of scientific data, there is not enough know about management of non-pulmonary nontuberculous mycobacterial infections. Nevertheless, it is admitted that treatment should be based on antimicrobial susceptibility testing and associate at least two antibiotics among which a macrolide for several months, usually four months in cutaneous infections and six month in bone infections. The national reference centre’s involvement seems necessary to optimize the care of those rare affections.