DERMATOPHYTE TEST MEDIUM (D.T.M.) AGAR

Technical Data #1233a / 2005.01.18

DTM Agar is a solid selective medium for isolation of pathogenic dermatophytic fungi from hair, skin and nails. Antibiotics inhibit bacteria and common molds. Pathogenic dermatophytic fungi produce alkaline reactions changing phenol red, pH indicator, from orange to red.

 

 

FORMULA
in grams per liter purified filtered water

Soy Peptone

10,0

Dextrose

10,0

Cycloheximide

0,4

Chloramphenicol

0,05

Phenol Red

0,2

Agar

20,0

Antibiotics

 

Gentamycin

0,1

Chlortetracycline

0,1

pH 5,5 +/- 0,2 à 25º C

This approximate formula may be adjusted and/or enriched to obtain best results.


PRECAUTIONS
This medium is for laboratory use only.


STORAGE
Store prepared media at 2-8º C protected from direct light and dehydrated powder, in a dry place, in tightly-sealed containers at 2-25º C.


SIGN OF DETERIORATION
Media should not be used if the expiry date has passed. Prepared media should not be used if there are signs of contamination or deterioration (shrinking, cracking, evaporation or discoloration). Do not use dehydrated media if it is caked.


DIRECTIONS
Suspend 40 g of dehydrated media in 1000 ml of purified filtered water. Heat with frequent agitation and boil for one minute. Sterilize at 121º C for 15 minutes. Cool to 45-50º C. Aseptically add antibiotics as required, mix gently and dispense into sterile Petri dishes or into steriles culture tubes.


PROCEDURE
Prior to inoculate, the prepared media should be brought to room temperature.

  1. Directly, inoculate media as soon as possible and press specimen gently into surface of the medium.
  2. Incubate at 25º C for up to 7 days.


QUALITY CONTROL
Results after 7 days at 25ºC

Organisms

ATCC

Growth

Trichophyton rubrum

clinical

+ red

Candida albicans

10231

- /partial, reddish

Stapylocococcus aureus

25923

- /partial


LIMITATIONS OF METHOD
A positive reaction in color may occur if specimens are higly contaminated. For this reason, a positive reaction after 10 days should be considered as negative. This medium is only a part of the identification. Other tests may be required.


REFERENCES

  1. Lennette, E.H., Ballows, A., Hausler, W.J.Jr., and Shadomy, H.J. Manual of Clinical Microbiology. 4th ed. 1985 Washington D.C.: American society for Microbiology.
  2. Mac Faddin, Jean F., 1985 Media for Isolation-Cultivation-Identification-Maintenance of Medical Bacteria. Vol.1. Baltimore, MD.: Williams & Wilkins.
  3. Taplin, D., N. Zaias, G. Rebell, H. Blank 1969 Isolation and recognition of dermatophytes on a new medium (DTM). Arch. Dermatol. 99:203


CATALOGUE NUMBERS

Dehydrated media 500 g QB-39-3021
     
Prepared media    
Mycobiotic/DTM Bi-Plates, 100x15 mm 10/pkg 1233M
Tubes, 20x125 mm 10/pkg 2766

 

 

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