Proteolytic activity of dermatophytes and its role in the pathogenesis of skin lesions

Proteolytic activity of 101 isolates of dermatophytes, Trichophyton rubrum, 92; T. mentagrophytes, 5; T. violaceum, 2 and Epidermophyton floccosum, 2; from 158 patients was determined using egg albumin as the substrate. The values were 0·76 – 10·63 mg tyrosine/100 mg fungal mat for T. rubrum; 11·25 – 15·66 mg for T. mentagrophytes; 10·28 – 18·25 mg for T. violaceum and 0·60 – 6·19 mg for E. floccosum. The inflammatory reaction was related to the proteolytic activity of T. mentagrophytes but not of T. rubrum.Intradermal injections of 11 fungal extracts into excised human skin produced spongiosis in all and dermo-epidermal splits in 7. Twenty-five fungal extracts injected intradermally in dogs resulted in erythema and induration at the sites of injection within 6 h which increased in intensity till 72 h. These sites revealed spongiosis, dermo-epidermal splits and inflammation. Application of fungal extracts on the stripped forearm skin of 15 human volunteers produced erythema in all and papulovesicles in 3....