Page 73 - MNUmicrobiology practical 2025

General Microbiology & Immunology (PM 401) second level Semester 4 2024/2025

smear is then rinsed with a very strong decolorizer, which strips the stain from

all non-acid-fast cells but does not permeate the cell wall of acid-fast organisms.

The decolorized non-acid-fast cells then take up the counterstain, which in our

case is methylene blue.

Acid fast staining requirements

1- Stock culture containing non acid fast organism #1

2-Stock culture containing acid fast organism #2

3- Clean microscope slides

4- Acid fast’s staining reagents

- Carbol fuchsin [primary stain]

- Acid-Alcohol (HCl + 95% ethyl alcohol) or (25% H2so4)[ Decolorizing agent]

General Microbiology & Immunology (PM 401) Practical note Page 62