Acid-Fast Bacteria

species of bacteria whose cells are not decolorized by sulfuric acid when stained with carbolfuchsin, owing to the chemical composition of the bacterial cells. The optimal reaction of the culture medium for growing acid-fast bacteria is not acid but neutral. Among acid-fast bacteria are several species of Mycobacterium, including pathogenic ones causing leprosy and tuberculosis in both man and animals and some nitrogen-fixing bacteria found in the soil.