VMC 211: General Veterinary Microbiology (1+1)

PRINCIPLE

• The capsule is gelatinous in nature. Because of this it is difficult to stain the capsule, hence special staining methods are used.
• The bacterial capsule is demonstrated by negative staining method. In negative staining the object is not stained but the background is stained. Hence object appears as colourless particle in a dark background.
• Normally the objects that are difficult to stain or that wont take any stain are stained are stained by negative staining method.
• One of the best reagent to produce dark background is the India ink used for drawing. Since the bacterial capsules are gelatinous nature they wont take any stain. In a black background the capsules appear as halos.
• The organisms are stained by simple stain like crystal violet.