Yeast Extract Soy Agar is used for the selective isolation of dermatophytes and other pathogenic fungi in clinical samples. This medium is the preferred method as the use of antibiotics for suppressing bacteria results in a better recovery of fungal cells, which are sensitive to an acid environment. Yeast Extract Soy Agar is a modification of Sabouraud Medium and was formulated by Carmichael and Claus for the selective isolation of Trychophyton verrucossum as well as other fungi associated with contagious diseases. It contains streptomycin and chloramphenicol, antibiotics that inhibit bacterial growth but allow for the detection of pathogenic fungi. Soy peptone provides nitrogen, vitamins, minerals, and amino acids essential for growth. Yeast extract is a source of vitamins, particularly of the B-group. Dextrose is the fermentable carbohydrate providing carbon and energy. Bacteriological agar is the solidifying agent.