17th February 2025

Non-tuberculous mycobacteria

Non-tuberculous mycobacteria are organisms that mostly affect the immunosuppressed or those with chronic lung disease.

Most prevalent is a Mycobacterium avium complex (MAC) syndrome, caused by an array of non-tuberculous mycobacterium which conolonsie the respiratory tract of humans but are not usually pathogenic in the immunocompetent. There is an occupational risk for those who work with contaminated water or certain animals. Rarely, chronic cough suppression can lead to non-tuberculosis mycobacterium infiltration, a phenomenon typically seen in elderly women known as Lady Windermere syndrome.

Symptoms are often non specific but may include a chronic productive cough, anorexia and fatigue. Mycobacterial treatment medications such as rifampicin may be employed if the infection is causing sufficient symptoms.

Notable species include:

• Mycobacterium marinum: may cause pulmonary disease and is related to working with fish
• M. Leprae: one of the causative organisms of leprosy
• M. Bovis: causes tuberculosis in cattle but can cause a tuberculous-like disease in humans
• M. Africanum: most common in West Africa; can cause a tuberculous-like pulmonary disease