Dermatophyte Test Medium (DTM)

Dermatophyte Test Medium is used for the selective isolation of dermatophytic fungi and is not intended for use in the diagnosis of disease or other conditions in humans.

In 1969, Taplin et al. developed this medium for the isolation and recognition of dermatophytic fungi, the causative agent of ringworm from hair, nails, and skin. Dermatophyte Test Medium is preferred for isolation and early recognition of Microsporum, Trichophyton, and Epidermophyton genera because of a distinct color change in the medium. Rapidly-growing species may produce a complete color change in the medium in 3 days. The slower-growing species will change the indicator in longer time periods. Other organisms may grow but can be recognized as non-dermatophytes by lack of a color change. A few organisms, including saprophytes, yeasts, and bacteria are capable of changing the medium from red to yellow, but are easily recognized by their distinctive colonial morphology.