Fishmeal Extract Dextrose Agar-A New Mycological Medium-A Preliminary Report

A new mycological medium, Fishmeal Extract Dextrose Agar (FEDA) was developed using aqueous extract of fishmeal as a substitute for peptone and evaluated for its efficacy in supporting the growth of fungi commonly encountered in clinical specimens and in maintaining fungal stock cultures. Trichophyton rubrum, Trichophyton mentagrophyte, Microsporum gypsium, Microsporum nanum, Epidermophyton floccosum, Aspergillus niger, Aspergillus fumigatus, Aspergillus flavus, Mucor spp., Rhizopus spp., Cryptococcus neoformans and Candida albicans, from stock cultures and/or from clinical specimens such as ear swab, urine and skin scrapings were successfully grown and preserved on FEDA containing 5% fishmeal extract, 2% dextrose and 2.5% agar at pH 7.0. The media was made selective for growing dermatophytes using antibiotics and cycloheximide. The results were compared with those on Sabouraud’s dextrose agar (SDA) and found 100% conformity. An important advantage of FEDA was that dermatophytes were maintained better on this medium. Fishmeal, a cake obtained after extraction of oil from sardines used in the preparation of fishmeal extract was found to be 100 times cheaper, non-hygroscopic and could be stored without special precautions unlike peptone used in SDA. Hence FEDA may be a useful medium for primary isolation of fungi in culture and maintenance of stock cultures in the developing countries where stringent cost containment is a primary requirement in the laboratory diagnosis of diseases.