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BAM Media M183: Dichloran rose bengal chloramphenicol (DRBC) agar

January 2001

Bacteriological Analytical Manual

M183
Dichloran rose bengal chloramphenicol (DRBC) agar

Glucose10.0 g
Bacteriological peptone5.0 g
Potassium phosphate, monobasic1.0 g
Magnesium sulfate heptahydrate0.5 g
Rose bengal
(5% soln., w/v)
0.5 ml
Dichloran (2,6-dichloro-4-nitroaniline) solution
(0.2%(w/v) in ethanol)
1.0 ml
Chloramphenicol0.1 g
Distilled water1 liter
Agar15.0 g

 

Final pH should be 5.6. Mix ingredients, heat to dissolve agar and sterilize by autoclaving at 121°C for 15 min. Temper to 45 ± 1°C in a water bath and pour plates.

 

Notes:

  1. DRBC agar is especially useful for analyzing sample containing "spreader" molds (e.g. Mucor, Rhizopus, etc.), since the added dichloran and rose bengal effectively slow down the growth of fast-growing fungi, thus readily allowing detection of other yeast and mold propagules, which have lower growth rates.
  2. Media containing rose bengal are light-sensitive;
    relatively short exposure to light will result in the formation of inhibitory compounds. Keep these media in a dark, cool place until used. DRBC agar should be used for spread plates only.

 


Original Source: Bacteriological Analytical Manual, 8th Edition, Revision A, 1998.