Comparative study of different microscopic techniques and culture media for the isolation of dermatophytes

To evaluate the usefulness of two different microscopic techniques and three different culture media for the identification and isolation of dermatophytes from clinical samples.

Skin, hair and nail samples from 260 clinically suspected cases of dermatophytosis were screened by direct microscopic examination using 10% potassium hydroxide (KOH) with and without 40% dimethyl sulphoxide (DMSO) mounts. All the samples were inoculated for culture in Sabouraud dextrose agar (SDA), dermatophyte test medium (DTM) and ready to use enriched dermatophyte medium (EDM).

Fungal elements were detected in 157 samples by both the methods but faster and better visualization was noted with 40% DMSO added to 10% KOH. Fungi were recovered from SDA, DTM and EDM in 96.5%, 98.3% and 85.3% of the cases respectively.

When performing direct microscopic examination of skin, hair and nail for dermatophytes, addition of 40% DMSO to the KOH mount gives better and faster results. The efficiency of SDA and DTM was found almost equal and slightly better than EDM. The EDM, although quite efficient with 85.3% isolation rate, requires further evaluation as its ready to use format makes the application and microscopy much easier and faster.