The dermatophyte, Microsporum gypseum, as a saprophyte and parasite.

Vanbreuseghem (1) recently described a selective procedure for isolating keratinophilic fungi from soil. The method extends the work of Karling (2), who first used keratin in various forms as bait for the isolation of chytrids from soil and water. Vanbreuseghem placed hair filaments upon the surface of moistened soil in which Trichophyton mentagrophytes (Ctenomyces interdigitalis), T. rubrum and Epidermophyton fioccosum had been grown. After a few days, the hair bait became visibly overgrown by mycelium which was noted to be penetrating the hair shafts by means of "perforating organs" (Vanbreuseghem, 3). f Cultures made from the invaded hair yielded T. rubrum and E. floccosum, but were negative for T. mentagrophytes. Previous attempts to isolate these dermatophytes directly from the test soils had ended in failure, due to overgrowth of the culture tubes by saprophytic molds, which had contaminated the soils during some prior manipulations. Vanbreuseghem examined a number of natural soils with his technic and isolated a keratinophilic fungus which subsequently was designated to be a member of a new genus Keratinomyces and given the specific name of K. ajelloi (4). However, none of the known dermatophytes was isolated from th Belgian soils studied. The present paper records the successful isolation of a known dermatophyte from natural soils baited with hair.