Dermatophyte test medium

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Dermatophyte test medium (DTM) is a specialized agar used in medical mycology.{{Cite web|url=https://foodsafety.neogen.com/en/acumedia|title=Acumedia Dehydrated Culture Media | Food Safety | Neogen|website=foodsafety.neogen.com}}{{Cite web|url=https://www.bd.com/en-us/offerings/capabilities/microbiology-solutions/microbiology-solutions-resource-library|title=Microbiology Solutions Resource Library|website=www.bd.com}} It is based on Sabouraud's dextrose agar with added cycloheximide to inhibit saprotrophic growth, antibiotic to inhibit bacterial growth, and phenol red a pH indicator. The pH indicator is useful in distinguishing a dermatophyte fungus, which utilizes nitrogenous material for preferred metabolism, producing alkaline by-products, imparting a red color change to the medium. Typical saprotrophic fungi utilize carbohydrates in the medium producing acidic by-products and no red color change.