Mycological Examination of Tinea Pedis Lesions Using a Cotton-swab Sampling Method

Abstract

A cotton-swab sampling method combined with Sabouraud’s dextrose agar supplemented with antibiotics was applied for the mycological examinations of tinea pedis lesions. A comparison of the results obtained by the cotton-swab method with those using an ordinary culture method revealed that both methods were almost equally useful as far as the culture rate is concerned, but the latter was superior for skin used as the subject for fungus culture, when there were no pathological changes. The method was applied to the examination of a supposed small epidemic of tinea pedis in a group of 22 females living together in a dormitory in Nagasaki. In four patients tinea pedis (2 due to Trichophyton rubrum and 2 due to Trichophyton mentagraphytes) was mycologically confirmed. In three females, T. mentagrophytes was isolated from clinically normal interdigital spaces. In 10, who were suffering from either maceration or desquamation, the mycological examination failed to demonstrate the presence of the fungi by either potassium hydroxide preparations and cultures using an ordinary inoculation method or by the cotton-swab sampling method. It is concluded that the skin lesions of the group were in most part due to the local conditions in the shoes which they were forced to wear during their work. The significance of the presence of T. mentagrophytes on the clinically normal skin surface is also discussed.