GRAMS STAIN (ASCITIC FLUID)

Overview

The Gram stain is a method of staining used to classify bacterial species into two large groups: Gram-positive bacteria and Gram-negative bacteria. Gram-positive cells have a thick layer of peptidoglycan in the cell wall that retains the primary stain, crystal violet. Gram-negative cells have a thinner peptidoglycan layer that allows the crystal violet to wash out on addition of ethanol. They are stained pink or red by the counterstain. Gram staining is almost always the first step in the preliminary identification of a bacterial organism and provides valuable information for selecting appropriate antibiotics for treatment.