acid-fast bacillus


ac·id-fast ba·cil·lus

(AFB) (asid-fast bă-silŭs) A type of bacterium that reacts in a given way when treated with an acid bath.

acid-fast bacillus

Abbreviation: AFB
A bacillus not readily decolorized by acids or other means when stained. Mycobacterium tuberculosis is an acid-fast bacillus. See also: bacillus