Acid Fast

∞ generated and posted on 2016.01.09 ∞

Bacteria with waxy cell envelopes which, once stained, resist destaining using low pH decolorizing agent.

Using biological stains that are capable of being removed using an acidic destaining agent, an Acid Fast organism is one that is capable, once stained, of resisting the removal of those stains using those acidic destaining agents.

Most notable among acid-fast organisms are members of genus Mycobacterium. Note that there are various additional bacteria as well as non-bacteria structures that also are acid fast in their staining characteristics.

See acid fast stain/Ziehl-Neelsen stain.

Note that the concept of acid fast should not be confused with that of acidic dye nor acidophile.