In vitro nail invasion by pathogenic and non-pathogenic fungi under different culture conditions.

Data from the literature suggest that the nutritional environment can modify major metabolic functions of fungi and possibly their aggressivity towards keratinous structures. Trichophyton rubrum (TR), Microsporum canis (MC), Scopulariopsis brevicaulis (SB), Aspergillus fumigatus (AF) and Penicillium spec. (P) were inoculated on media of different nutritional value, in presence of nail fragments. The activity of the fungi was evaluated at two and four weeks for intensity and depth of invasion of nail samples. Nail invasion was most pronounced by MC, especially when grown on rice agar or peptone agar. Nail invasion by the other fungi tested was less important, Sabourand glucose and rice agar were most favorable. Our results indicate that nutritional factors can, at least in some fungus species, alter their rate of nail invasion.