Skin infections caused by <i>Mycobacterium chelonae</i>: Underestimated, especially in immunocompromised patients

Abstract Mycobacterium chelonae infections are rare but significant in immunocompromised patients, often leading to delayed diagnosis due to a specific clinical signs and the difficulty to culture and identify the causative agent with conventional laboratory techniques. We report a case series of five patients presenting with cutaneous infection due to M. chelonae . An extensive review of the literature was accomplished to provide summary data on the clinical presentation, diagnostic methods and treatment options for these infections. Four out of five patients were receiving immunosuppressive treatments. All patients presented after a prolonged history of painful lesions on the extremities. Sampling and definitive diagnosis implied repeated tissue biopsies and a combination of mycobacterial tests. All patients received a combination of antibiotics comprising a macrolide and achieved complete healing of the skin lesions after 4–12 months. Our case report aims to increase awareness of skin infections caused by M. chelonae and emphasises the importance of early implementation of mycobacterial cultures in the diagnosis of painful ulcerations on the extremities that do not improve to standard systemic antibiotics.