Gram Staining Procedure
ram staining is the most important procedure in microbiology that was developed by Danish physician
Hans Christian Gram in 1884. Gram staining is the basis of bacterial identification and taxonomic
division, This differential staining procedure separates most bacteria into two groups on the basis of cell
wall composition:Gram positive and Gram negative. In Gram staining process, when the bacteria are stained with primary stain Crystal Violet (CV) and fixed by the mordant (iodine solution) some of the bacteria are able to retain the primary stain (Gram positive) and some are decolourised by washing with alcohol (Gram negative). Gram negative bacteria take up safranin, the counter dye and appear red or pink in colour.
