Capsule Staining Technique by Maneval’s Method, Requirement, Procedure

Capsule Staining Technique by Maneval’s Method.

Principle  

The principle of capsule staining is based on staining of background with an acidic stain and staining of bacterial cell with a basic stain. A capsule being non-ionic will not stain by either of the two dyes. Thus, capsule staining creates contrast by staining a bacterial cell along with its background and leaving a capsule as a colorless halo. The other approach of capsule staining is to stain the capsule by leaving a bacterial cell and background colorless. Differential capsule stains are available to highlight the specific structure (like capsule) in a bacterial cell.

Requirement

1. 1 % Congo red solution.
2. Maneval’s stain.
3. Capsulated cell culture.

Procedure

1. Take a loopful of capsulated cell suspension on a clean grease-free slide.
2. Add a drop of 1 % congo red solution in the suspension and then spread it gently on the slide to form a smear.
3. Allow the suspension to air dry and do not heat fix it.
4. Flood the slid with Maneval’s stain and keep it for 2 minutes.
5. After 2 minutes discard excess stain and do not water wash the slide.
6. Allow the slide to air dry and observe under oil immersion objective.  

      

Result

Capsule Staining Technique by Maneval’s Method.

color of cell : pink to red

colour of background : blue to violet

color of capsule :  colourless