Gram's stain is a method used to differentiate between two large groups of bacteria - Gram positive and Gram negative - based on their cell wall structure and composition. The staining process involves smearing a bacterial sample on a slide, treating it with crystal violet dye and iodine, then decolorizing it with alcohol or acetone before counterstaining with safranin. This allows bacteria to be classified based on whether they retain the primary violet stain (Gram positive) or take up the counterstain (Gram negative).

1. PRACTICAL
MICROBIOLOGY
Gram’s stain

2. Gram’s stain
Gram staining (or Gram's method) is a method of
differentiating bacterial species into two large groups
Gram Positive Gram negative
Gram staining differentiates bacteria by the chemical and
physical properties of their cell walls.

4. Dyes and chemicals used in staining

5. What happens in staining process!!!

6. • 1. smear preparation
Procedure

8. Staining procedure

9. Results

10. Examples
Gram –ve bacilli Gram +ve cocci