DESCRIPTIONS OF MEDICAL FUNGI

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Descriptions of Medical Fungi
MICROSCOPY STAINS & TECHNIQUES
Lactophenol Cotton Blue (LPCB)
For the staining and microscopic identification of fungi.
Cotton Blue (Aniline Blue)
0.05 g
Phenol Crystals
20 g
Glycerol
40 mL
Lactic acid
20 mL
Distilled water
20 mL
This stain is prepared over two days.
1. On the first day, dissolve the cotton blue in the distilled water. Leave
overnight to eliminate insoluble dye.
2. On the second day, wearing gloves, add the phenol crystals to the lactic
acid in a glass beaker. Place on magnetic stirrer until the phenol is
dissolved.
3. Add the glycerol.
4. Filter the cotton blue and distilled water solution into the phenol/glycerol/
lactic acid solution. Mix and store at room temperature.
Direct Microscopic Mounts or Squash Preparations
Using sterile technique, remove a small portion of the colony with an inoculation needle
and mount in a drop of lactophenol cotton blue on a clean microscope slide. Cover with
a coverslip, squash the preparation with the butt of the inoculation needle and then blot
off the excess fluid.
Cellotape Flag Preparations
An excellent technique for the rapid mounting of sporulating fungi because it keeps
more of the reproductive structures intact.
1. Using clear 2 cm wide cellotape and a wooden applicator stick (orange
stick) make a small cellotape flag (2 x 2 cm).
2. Using sterile technique, gently press the sticky side of the flag onto the
surface of the culture.
3. Remove and apply a drop of 95% alcohol to the flag, this acts as a
wetting agent and also dissolves the adhesive glue holding the flag to
the applicator stick.
4. Place the flag onto a small drop of lactophenol cotton blue on a clean
glass slide, remove the applicator stick and discard, add another drop of
stain, cover with a coverslip, gently press and mop up any excess stain.