Classification of Nontuberculous Mycobacteria – Microbiology MCQ

All of the following are non photochromogens except?
A. Mycobacterium ulcerans
B. Mycobacterium xenopi
C. Mycobacterium avium
D. Mycobacterium marinum

Correct answer : D. Mycobacterium marinum

Classification of non tuberculous mycobacteria:

• Photochromogens – produce pigment when exposed to light. eg: M. kansasii, M. marinum.
• Scotochromogens – produce pigment in the dark. eg: M. scrofulaceum, M. gordonae.
• Non photochromogens – do not produce pigment even when exposed to light. eg: M. ulcerans, M. xenopi, M. avium.
• Rapid growers – growth within seven days. eg: M. fortuitum, M. chelonae.