The faviform UV-mutants of Microsporum cookei, Trichophyton ajelloi and Trichophyton mentagrophytes are described. Two of the eight faviform mutants of T. mentagrophytes were pathogenic for guinea pigs, the others were non-pathogenic. The changed morphology of faviform mutants derived from T. mentagrophytes was permanent even after recultivation from animal lesion. The authors classify faviform changes known up to now into three categories: 1. Faviform modifications (reversible reaction of culture on specific environmental factors). 2. Faviform mutations (irreversible changes of cultures). 3. Syndrome of faviform senescence (spontaneous change in old cultures of dermatophytes probably caused by mutation in cytoplasmic or nuclear determinant).
Hejtmánek M., Lenhart K. (1970): Contribution to faviform variability and pathogenicity of dermatophytes. – Česká Mykologie 24(4): 192–197.
