BROWN-BRENN MODIFICATION OF GRAM STAIN

                                                             BROWN BRENN STAINING 

    It is a modified gram staining technique used in pathology for the demonstration of bacteria in tissue samples.

    The principle used here is similar to that of gram staining. The same cell wall theory of bacteria is utilized here.

Reagents:

    1% Crystal violet

    Lugol's Iodine

    Acetone

    0.25%Basic Fuchsin

    Picric Acid-acetone

Procedure:

1. Add crystal violet into the tissue section and allow it to stand for 1 minute

2. Wash and add Lugol's Iodine for 1 minute.

3. Wash again and add acetone over the section until no color turns off.

4. Wash the slide and pour basic fuchsin and stain for 3 minutes.

5. Wash and dip quickly into acetone - 2 dips.

6. Dip the slide directly into the Picric-acetone mixture.

7. Dip quickly into two changes of acetone.

8. Air dry, and dip it into xylene, and place a coverslip over it. Observe under the microscope.

Observation:

Gram-positive bacteria appear -  Blue

Gram-negative bacteria appear - Red

Nuclei of Cells appear - Red

The background appears - Yellow