Which atypical mycobacterium causes disseminated infection specifically in patients with idiopathic CD4+ lymphocytopenia or those with a genetic defect in the IFN-gamma/IL-12 axis?

• A Mycobacterium kansasii
• B Mycobacterium marinum
• C Mycobacterium fortuitum
• D Mycobacterium avium complex (MAC) ✓

Explanation

MAC (M. avium-intracellulare complex) is the most common atypical mycobacterium causing disseminated infection in immunocompromised states; it specifically colonizes the GI tract and causes disseminated disease when CD4 count falls below 50 cells/μL in HIV or in genetic defects of IL-12/IFN-gamma axis (Mendelian susceptibility to mycobacterial disease, MSMD). M. kansasii causes pulmonary disease similar to TB. M. marinum causes fish-tank granuloma (cutaneous). M. fortuitum causes skin and soft tissue infections after trauma or injections.

Reference: Ananthanarayan & Paniker's Textbook of Microbiology, 11th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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