Microbiology Procedure
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Rapid Method for Gram Stain

Rapid method for Gram stain
It should be recognized that the time quoted in the methods for staining have little basis in critical examination of the Gram staining results. Many investigators involved in routine diagnostic work have evolved procedures which are highly effective and time saving. A common technique is described here. Take a heat fixed smear and allow the crystal violet solution (S23) to run over the smear and wash it with undiluted Grams iodine (S24) solution.

Decolourize imme­diately with alcohol acetone (1:1) mixture and wash briefly with water. Counterstain with safranin (S25) for 5 seconds. Wash, dry and examine under oil-immersion objective. With a little practice it is possible to produce a good Gram stain in 15-20 seconds by this method.

Gram positive cells appear violet while Gram negative cells appear pink in colour. The general morphology and Gram reaction of some of the common bacterial genera is listed in Table.

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