Question

What are the principle of acid fast staning ​

Answer 1

Explanation:

Principle of acid fast staining (in mycobacteria):

Heat softens the wax in the cell wall and allows the stain (basic fuchsin) to enter. The fuchsin dye is more soluble in phenol than in water or alcohol. Phenol in turn is more soluble in lipids or waxes, thus the dye-phenol mixture enters the cell.

Answer 2

Answer: The principle of Acid Fast Staining is as follows

It used as an alternative to Gram stain

• When the smear is stained with carbol fuchsin, it solubilizes the lipoidal material present in the Mycobacterial cell wall but by the application of heat, carbol fuchsin further penetrates through lipoidal wall and enters into cytoplasm. Then after all cell appears red.

• Then the smear is decolorized with decolorizing agent  but the acid fast cells are resistant due to the presence of large amount of lipoidal material in their cell wall which prevents the penetration of decolorizing solution.

• The non-acid fast organism lack the lipoidal material in their cell wall due to which they are easily decolorized, leaving the cells colorless.

• Then the smear is stained with counterstain, methylene blue.

• Only decolorized cells absorb the counter stain and take its color and appears blue while acid-fast cells retain the red color.