Comparison of methods for isolation of dematiaceous fungi from nature

Direct plating and animal inoculation techniques were compared for effectiveness in isolating dematiaceous fungi from nature. The direct plating technique involved comparison of aqueous and mineral oil extraction of the samples with subsequent plating on Mycobiotic and Sabhi agar. Twenty four different organisms were recovered from 19 samples using both extraction procedures and both media. Dematiaceous fungi isolated by direct plating were Alternaria alternata, Cladosporium spp., Exophiala jeanselmei, Wangiella dermatitidis and 6 unidentified organisms. Direct plating resulted in more isolations of dematiaceous fungi partly because of the frequent isolations of A. alternata and W. dermatitidis. Both more and a larger variety of organisms were recovered on Mycobiotic than on Sabhi agar. The aqueous extraction of samples resulted in more direct plating isolations of fungi than oil extraction.