Technical Data
Dermatophyte Test Medium (DTM Test Agar) (Powder)
Microbiological Grade
Storage 4C    Shipping RT
Formulation per Liter
Components shown as g/L
Phenol Red0.2
Soy Peptone10.0
Supplements (Added post autoclaving):
Dermatophyte Test Medium is used for the selective isolation of dermatophyic fungi.

In 1969, Taplin, et al. developed Dermatophyte Test Medium for the isolation and recognition of dermatophytic fungi, the causative gent 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 three days. The slower growing species will change the indicator in longer time periods. Other organisms may grow. These can be recognizes as nondermatophytes by lack of color change. A few organisms, including saprophytes, yeasts and bacteria are capable of changing the medium from red to yellow. These are easily recognzied by their distinctive colonial morphology.

Soy Peptone provides nitrogen and vitamins required for organism growth. Dextrose is included as an energy source. Phenol Red is the pH indicator used to detect acid production. Cycloheximide inhibits most saprophytic molds. The supplements, Gentamicin and Chlortetracycline, aid in selectivity of Dermatophyte Test Medium. Gentamicin inhibits gram-negative bacteria including Pseudomonas spp.. Chlortetracycline is a broad-spectrum antibiotic, inhibiting a wide range of gram-positive and gram-negative bacteria. Agar is the solidifying agent.

Directions per Liter: Suspend 40.7 grams of the powder in IL of purified water. Mix thoroughl. Heat wih frequent agitationand boil for 1 minute to dissolve the powder completely. Dispense into appropriate containers, loosen caps and autoclave for 15 minutes at 121C (15psi). Cool to 50C. Aseptically add sterile gentamicin (0.1g/L) and sterile chlortetracycline (0.1g/L).

Storage and Stability:Store powdered media at RT. Opened bottles should be capped tightly and kept in a dark, low humidity environment. Prepared media should be kept refrigerated and used within a short period of time.

Appearance: Off-white to beige, homogeneous, free flowing powder. Solubility

Important Note: This product as supplied is intended for research use only, not for use in human, therapeutic or diagnostic applications without the expressed written authorization of United States Biological.

1. Taplin, D., Zalas, N., Rebell, N., Blank, H.: Isolation and recognition of dermatophytes on a new medium (DTM). Arch Dermatol. 99: 203 (1969). 2. MacFaddin, J.: Media for isolation-cultivation-identification-maintenance of medical bacteria (vol 1). Williams and Wilkins, Baltimore, MD.