Gram Staining

Gram Staining

Gram Staining

1. Flood the fixed smear with Gram’s crystal violet Solution. Let stand for 60 seconds.
2. Pour off the stain and gently wash with tape water from a faucet or a plastic water bottle.
3. Flood with Gram’s iodine Solution. Allow it to remain for 60 seconds.
4. Pour off the iodine solution and gently wash with tape water. Shake off the excess water from the surface.
5. Decolorize with Gram’s Decolorizer Solution until the blue dye no longer flows from the smear. Further delay will cause excess decolorization in the gram-positive cells, and the purpose of staining will be defeated.
6. Gently wash the smear with tape water.
7. Counterstain with Gram’s safranin Solution for 60 seconds.
8. Wash off the red safranin solution with water. Blot with bibulous paper to remove the excess water. Alternatively, the slide may shaken to remove most of the water and air-dried.
9. Examine the finished slide under a microscope (oil immersion objective). Attention: Wash off any spilled stain immediately with water to avoid leaving permanent marks in the sink, lab bench, or glassware.

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