Staining is any microbiological process which increases the contrast of organisms when certain dyes or stains are applied to them prior to their examination under the microscope. It is generally the process of colouring specimens and microorganisms so that they can be easily observed and distinguished under the microscope.
Staining in the microbiology laboratory is usually carried out on dead microbial cells which must have undergone a series of smearing during smear preparation. In some scenarios, microbial cells are only stained once but staining can involve a series of process in which bacterial cells are stained several times using different types of dyes or counterstains meant to reveal certain features of the organism during examination under the microscope.
Some commonly used stains in the microbiology laboratory include crystal violet, methylene blue, lactophenol cotton blue, Giemsa stain, eosin stain, carbol fuchsin, acridine orange and fluorescent dyes amongst others. Gram staining, negative staining and acid fast staining are some of the commonly encountered staining techniques used in the microbiology laboratory.
Staining technique generally helps microbiologist to observe microbial cells under the microscope and describe them appropriately based on their ability to react with certain stains or dyes.
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