Mycoflora of the human dermal surfaces

Abstract

The mycotic flora of the scalp and interdigital areas of the hand and foot of 1296 apparently healthy human inhabitants of three Amazonian communities were surveyed by means of microscopic examination of epidermal scrapings and cultural isolation on Mycosel agar. No macroscopic or microscopic evidence of fungal infection was detected in any of our study subjects. From 133 (10%) individuals, 143 fungi representing 13 genera and 39 species were recovered. Yeasts constituted 85% of the fungi. Seventy-five percent of the isolates were fungi with pathogenic potential: Aureobasidium pullulans, Candida albicans, Candida guilliermondii, Candida parapsilosis, Candida stellatoidea, Candida tropicalis, Exophiala werneckii, Geotrichum candidum, Rhodotorula rubra, Torulopsis glabrata, Trichophyton tonsurans, Trichosporon cutaneum, and Wangiella dermatitidis. The low frequency with which each species was represented resulted in a mosaic distribution of the fungi with respect to human anatomical sites and study areas. The lack of similarity in species composition beteen the human dermal mycoflora and soil mycoflora in the same study areas supports the conclusion that distinct yeast species occupy different environmental niches.