Cryptococcus Neoformans Stain

Intended use:

Cryptococcosis specifically caused by Cryptococcus neoformans, is a subacute or chronic fungal infection. The purpose of the Indian ink preparation delineates the large capsule of C. neoformans.

Principle:

There exists mucopolysaccharide capsule around the bacterium cell, hence the presence of capsule can be confirmed with India ink wet mount preparations. The capsules of Cryptococcus neoformans replace India ink particles and will appear as clear haloes around the organisms.

Methods:

1. With an inoculating loop, transfer a 2~3 loops of culture (or a few solid culture suspended in a drop of physiological saline) and mix with a drop of India ink on slide.

2. With tweezer, place a coverslip over the culture. Note to place one side of coverslip to touch the culture and put down slowly, avoiding air bubble.

3. Identify the cells with capsule at low magnification and then confirm at high magnification.

Specifications:

Precaution:

Control the culture concentration:If the culture concentration is too high, then the bacteria will pile up and construction becomes difficult to observe. If the culture concentration is too few, take time to search. The liquid cannot be too much in order to avoid contamination when placing a coverslip.

Expected Results:

The capsules appear as clear haloes on dark background.