Utilization of Standard Laboratory Methods in the Laboratory Diagnosis of Problem Dermatophytes

The identification of certain dermatophytes may be simplified by using biochemical tests such as urease, nutritional requirements (with commercially available media), and the in-vitro hair penetration test. No study that combines these tests in a diagnostic scheme for identification of the common dermatophytes has been published. one to 20 isolates each of 29 species of dermatophytes (one Epidermophyton floccosum, 10 Microsporum species, and 18 Trichophyton species) were used. They were grown on Christensen's urea agar and the seven nutritional media for the differentiation of the Trichophyton species; the in-vitro hair penetration test was performed in duplicate. Patterns were developed that have been tested and proven to be useful for more than 22 months. In addition, the Microsporum species were all grown on polished rice, and color and sporulation were recorded. All dermatophytes in this study were grown on either Mycosel agar or 2% malt extract agar, and on modified potato dextrose agar and modified Sabouraud agar. Macroscopic and microscopic examinations were made to determine qualitatively the amounts of growth and sporulation on each medium.