Atypical Mycobacterial Disease

Atypical mycobacteria or nontuberculous mycobacteria are organisms that cause various diseases such as skin and soft tissue infection, lymphadenitis, pulmonary infection, disseminated infection, and a wide range of more rarely encountered infections. The most commonly encountered atypical mycobacteria that cause the majority of infection in humans are the Mycobacterium avium complex bacteria (MAC), Mycobacterium avium, and Mycobacterium intracellulare, also referred to as Mycobacterium avium-intracellulare (MAI), Mycobacterium kansasii, Mycobacterium marinum, Mycobacterium ulcerans, Mycobacterium abscessus complex bacteria (abscessus, massiliense, and bolletii), Mycobacterium chelonae, and Mycobacterium fortuitum. These organisms are most commonly found in the soil, indoor, and outdoor water sources and are recognized to colonize poorly sanitized medical equipment. Atypical mycobacteria most commonly infect young children, immunocompromised individuals, individuals with indwelling medical equipment, and those who have recently undergone surgical or non-surgical procedures. These bacteria can be further categorized into slow and rapidly growing organisms and grouped by the organ systems they commonly affect. Due to their morphology and growth patterns, atypical mycobacteria are challenging to identify on diagnostic testing. Treatment often requires extended courses of combination antibiotic therapy, frequently with surgical intervention.