Dermatophyte growth and degradation of human stratum corneum in vitro (pathogenesis of dermatophytosis).

BACKGROUND This study was carried out to determine growth of dermatophytes using human stratum corneum in vitro and the degrading effect of Keratinases (Proteinases) on stratum corneum for a complete understanding of the host parasite relationship. METHOD Trichophyton rubrum isolates derived from patients with tinea cruris infections were obtained from the Department of Medical Microbiology, University Hospital of Wales, U.K. Human stratum corneum sterilized with ethylene oxide was used as a nitrogen source in agar culture medium plates. RESULT Fungal growth took place in plates which contained human stratum corneum particles while there was no growth in the plates without stratum corneum at three weeks after initiation. There was a gradual disappearance of the particles of stratum corneum from the plates at the end of the third week CONCLUSION The growth of organisms in plates with human stratum corneum and their disappearance at third week suggested that stratum corneum was not only source of nutrition for the dermatophytes, but also the growing fungal mycelia and the proteinases induced by them were playing a part in the digestion of granules and thus may have an important role in the pathogenesis of dermatophyte infections.