It is prepared by dissolving 1 g Na 2S in 7.5 ml distilled water and subsequently adding 2.5 ml ethanol. Alternatively a part of each sample is examined in nail-dissolving solution containing a fluorochrome ( Monod et al, 1989). An example of a reactive solution is this. In the laboratory 20-30% potassium hydroxide solution is added to part of the specimen to macerate the nail keratin so that the specimen can be examined for fungal elements by direct microscopy. Scrapings taken with a blunt scalpel or clippings should be transported in a folded square of paper, preferably fastened with a paper clip, but commercial mycological packs are also available. The figure below shows the appropriate sites from which nail specimens should be obtained ( Denning et al, 1995).
Having a specimen taken should be painless apart from occasional slight discomfort when subungual specimens are taken. The quality of the specimen taken is a major factor in success or otherwise of microscopy and culture. A filamentous fungus in the CSF of a patient with meningitis that grew Candida albicans in culture subsequently.These cells may be mistaken for lymphocytes. neoformans cell seen in CSF in an AIDS patients with remarkably little capsule present. Transmission electron micrograph of a C.India ink preparation of CSF showing multiple yeasts with large capsules, and narrow buds to smaller daughter cells, typical of C.Persistently positive CSF findings in patients undergoing treatment should be considered evidence of failure or relapse only if they are confirmed by a deterioration in the patient’s clinical condition or by positive cultures. In persons with AIDS, Cryptococcus cells are usually plentiful in the CSF, although the capsules can be small, making recognition difficult. However, intact lymphocytes, in particular, can be confused with the organism. About 50% of HIV-negative and more than 80% of HIV-positive patients have a positive India ink examination of the CSF. Encapsulated Cryptococcus cells can often be detected in specimens of CSF or other host fluids or secretions mounted in India ink.
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