Microbiology: Laboratory Theory and Application: Capsule stain Flashcards
Composed of mucoid polysaccharides or polypeptides they repel most stains
How does the capsule technique take advantage of the capsule composition?
By staining around the cells
What stains (2) are used with capsule staining?
1. Acidic stain such as Congo red or nigrosin (stains background)
2. Basic Maneval's stain (stains the cell proper)
The capsule remains unstained and appears as a white halo between the cells and the colored background
Why are cells in a capsule stain not heat fixed?
Heat fixing causes the cells to shrink, leaving and artificial white halo around them that might be interpreted as a capsule
Describe capsule stain technique
This technique begins as negative stain, cells are spread as a film with an acidic stain and aren't heat fixed. In place of heat fixing cells may be emulsified in a drop of serum to promote their adhering to the glass slide
What type of stain is the capsule stain?
What's the purpose of the capsule?
The capsule production increases virulence in the microbes by making them less vulnerable to phagocytosis