Mycobacterium tuberculosis (Red stained) in contrast (methylene blue).
Acid-alcohol resistance is the physical property of some bacteria to the resistance to discoloration of the basic fuchsin (red) which penetrates the cell by the action of phenol and heat.
Acid-alcohol resistant bacteria can not be classified according to Gram staining, which is the most common technique in contemporary microbiology, however it can be stained with some concentrated stains combined with heat. Once dyed it has the ability to withstand the discoloration of a combination of alcohol-acid, which is the most common bleach in bacterial staining protocols, hence the name Alcohol-resistant acid.
The high concentration of mycolic acid in the cell wall is the cause, as bacteria of the genus Mycobacterium, of low absorption and high retention of staining (fucsina). The most common way to identify this type of bacteria is through the Ziehl-Neelsen staining technique, where the bacteria is stained red and a contrast dye of methylene blue is added, which allows better appreciation the bacteria.
Genus of Bacteria Resistant acid-alcohol The number of acid-alcohol resistant bacteria genera is very limited:
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