The pathogenesis of dermatophyte infections in human skin sections

Aim. A novel ex vivo model for the study of adherence and invasion of dermatophytes to the stratum corneum was developed. Materials and methods. A skin of full epidermis thickness was infected by spores of Trichophyton mentagrophytes and examined after various periods of time by scanning and transmission electron microscopy. Results. After 12 h of inoculation a tenacious adherence between the spores and the stratum corneum was observed. There was a time dependent increase in the number of spores adhered to this surface. By 24 h, germination had commenced. The initial growth of germ tubes occurred extracellularly to the corneocytes. Three days after inoculation, the most prominent feature was proliferation of fungal hyphae and penetration of mycelium through the outer keratinocyte Layer which is followed by invasion of the outer stratum corneum. Conclusion. The model introduced in the present study may contribute to a better understanding of the nature of the interaction between dermatophytes and skin cells in dermatophytosis process. (C) 2003 The British Infection Society. Published by Elsevier Ltd. All rights reserved.