Basic Principle
It is used to prepare mounts for microscopic study of fungi. This is most widely used
method for laboratory culture rather than clinical specimens.
Materials:
a. Lactophenol cotton blue stain
b. Fungal culture
c. Microscopic glass slides and cover glass
d. Other essentials
Stain composition:
Lactic acid 20 g
Phenol 20 g
Glycerin 40 g
Cotton blue 0.05 g
Distilled water 20 ml
Lactic acid and glycerin acts as clearing agent and preservative of fungi; phenol acts as
killing agent of fungi; cotton blue gives the colour to the structure allowing a better
microscopic observations.
Procedure:
a) Place a drop of lactophenol cotton blue stain on the clean glass slide.
b) With a bent needle, small amount of fungal growth mixed in the stain. Using a teasing
needle spread the fungal mycelium as much as possible.
c) Cover the preparation with a thin cover slip and examine under low (10X) followed by
high dry (45X) power magnification of microscope.
d) (Optional) Lactophenol cotton blue wet mount preparation can be preserved by sealing
the edge of the cover slip to the glass slide with finger nail polish or stencil correction
fluid.
Observations:
Fungal structure will appear as blue coloured body. Pigmented structures usually
appear intense blue or black.