Slow-growing NTM whose colonies become pigmented when exposed to light are referred to as:

Question

a. scotochromogens.
b. photochromogens.
c. nonphotochromogens.
d. chromogenicums.

Answer 1

B
Species of mycobacteria synthesize carotenoids (i.e., a group of pigments that are yellow to red) in varying amounts and are categorized into three groups, based on the production of these pig-ments—photochromogens, scotochromogens, and nonphotochromogens. The photochromogens are slow-growing NTM whose colonies become pigmented when exposed to light. The scotoch-romogens are slow-growing NTM whose colonies are pigmented when grown in the dark or the light. The nonphotochromogens are slow-growing NTM whose colonies produce no pigment whether they are grown in the dark or the light.