The effect of microwave irradiation on the vitality of various dermatophytes

Abstract

Dermatomycosis is one of the most common dermatological infectious diseases. In recent years, the incidence of tinea pedum, a fungal infection of the feet, was increasing due to changing lifestyles. The risk of tinea pedum infections is associated with the use of sport shoes as well as contact with public sports facilities. Transmission of dermatomycosis occurs almost exclusively through indirect contacts, meaning that contagious material initially contaminates the patients' environment and subsequently facilitates the spread of infection to others. A suitable disinfection procedure for 'fungal reservoirs' is very important in order to reduce the risk of reinfection of tinea pedum. This study investigates the effect of microwave radiation on various dermatophytes- (Trichophyton rubrum, T. rubrum var. nigricans, T. interdigitale and Microsporum canis infected cork and polyethylene sponge shoe insoles. The contaminated insoles were irradiated with various intensities and durations of microwaves. In each case, 10 colonies on cork and polyethylene sponge insoles were irradiated with the same intensity and duration, and subsequently compared with those of corresponding non-irradiated control groups. Results of three independent experiments were statistically verified using Chi-squared test for significance. We found significant differences between the various dermatophytes on polyethylene sponge insoles and also partly on cork insoles for the same irradiation intensity and duration. We were also able to show that a complete growth inhibition of all four dermatophytes occurs on both types of insoles after a 30s exposure at 560W, including a maximum temperature of 60°C.