Heat resistance of dermatophyte's conidiospores from athletes kits stored in Nigerian University Sport's Center.

The incidence and heat resistance of conidiospores produced by dermatophytes isolated from athlete's kits (canvasses, stockings and spike shoes) stored in Nigerian University Sport's Centre were investigated. Epidermophyton floccosum, Microsporum oudouinii, Microsporum canis, Trichophyton concentricum, Trichophyton mentagrophytes and Trichophyton rubrum were isolated and their incidence on the athlete's kits varied with the species and type of kits. Among the isolates T. mentagrophytes, T. rubrum and E. floccosum with 25%, 23% and 20% prevalence rates respectively, were the most common isolates, and are often associated with tinea pedis (athletes foot). Canvasses with the highest incidence of dermatophytes (25 out of 34 fungal isolates) were the most contaminated kits and could serve as effective articles for the transmission of tinea pedis among athletes in Nigeria. The common etiological agents screened, produced asexual spores (conidiospores) that exhibited high resistance to heat treatment at 80 degrees C. Of the three isolates, E. floccosum, with a decimal reduction time (D-value) of D80 = 4.4 min was the most resistant followed by T. mentagrophytes with D80 = 4.0 min and then T. rubrum with D80 = 3.2 min. The spores elimination pattern indicates that increasing the heating duration would decrease the decimal reduction time and possibly denature the fungal propagules but may damage the skin during treatment with hot water compresses. The findings have shown that the use of hot water compresses is palliative but heat treatment especially vapour-heat treatment offers adequate preventive measures if applied for periodic treatment of contaminated kits. However, determining the correct condition for effective decontamination will require detailed understanding of the heat resistance of fungal spores. Otherwise treatment of kits with detergent and chaotropic agent such as urea and guanidinium salt is preferred to heat treatment.

Growth, keratinolytic proteinase activity and thermotolerance of dermatophytes associated with alopecia in Uyo, Nigeria.

Mycological research was conducted on the mycelial growth, keratinolytic proteinase activity and thermotolerance ofdermatophytes associated with alopecia patients in Uyo, Nigeria. The results revealed that Microsporum sp. - AP1, Epidermophyton sp. - AP2, Trichophyton rubrum - AP4, Trichophyton mentagrophytes - AP5 and a yeast Candida albicans - AP3 isolated exhibited variable growth and keratinase activity at different temperatures. Microsporum sp. - AP1 and T. mentagrophytes - AP5 survived heat treatment at 90 degrees C but exhibited best mycelial growth at 30 degrees C (with 53.41 mg/50 ml biomass dry weight) and 40 degrees C (with 61.32 mg/50 ml biomass dry weight) respectively, after incubation for 2 weeks. Trichophyton rubrum - AP4 and Epidermophyton sp. - AP2 could not survive heat treatment at 90 degrees C but grew better at 40 degrees C (with 38.52 mg/50 ml biomass dry weight) and 30 degrees C (with 48.32 mg/50 ml biomass dry weight) respectively, over the same incubation period, while C. albicans - AP3 grew better at 30 degrees C with 38.7 mg/50 ml biomass dry weight after 2 weeks, but failed to survive at 70 degrees C. All the isolates except Candida albicans - AP3 survived at 80 degrees C and exhibited great potential to elaborate keratinolytic enzymes, with T. mentagrophytes demonstrating the best potential at 30 degrees C and 40 degrees C. Higher temperatures tended to reduce keratinolytic activities and there were significant (P < 0.05) relationships between biomass weight and enzyme productivities of all the isolates except T. mentagrophytes. This indicates that in some dermatophytes keratinolytic proteinase activity is not a function of cell multiplicity. This plus the high thermostability of the enzymes are important attributes in the consideration of preventive and therapeutic methods against dermatophytes in the tropics.