How are staining techniques classified?
Simple stain: where only one stain is used and all bacteria are stained similarly. Eg: Methylene blue, dilute carbol fuchsin Differential staining: where different bacteria stain differently to a common staining technique depending on their physiological properties. Eg: Grams stain and Acid fast staining Special stain: where structures of bacteria like spores, granules, capsule etc are demonstrated. Eg: silver impregnation technique for demonstration of spirochetes, Feulgen stain for demonstration of nucleus, Sudan black stain for demonstration of lipid vacuoles, Ryus stain for demonstration of flagella, Alberts stain for demonstration of metachromatic granules. Negative staining: where the background is stained with an acidic dye such as India ink or Nigrosin. Used for demonstration of capsules.
