Cetrimide Agar

Cetrimide Agar

SKU: KM0059 Category:

Cetrimide agar is a selective medium for the isolation and detection of Pseudomonas aeruginosa from pharmaceutical, clinical and cosmetic samples. The formulation is complaint with the requirements of the Harmonised USP/EP/JP.
Detection is achieved using the unique ability of P. aeruginosa to produce the water soluble, bright green pigment pyocyanin. The production of this pigment is stimulated by the presence of magnesium chloride and di-potassium sulphate in the medium. The addition of glycerol (10ml/l) is required as this compound serves as an energy source. Cetrimide, a quaternary ammonium compound, is also present to suppress the growth of other Pseudomonas spp. as well as Gram-negative and Gram-positive organisms. Pancreatic digest of gelatin provides the required nitrogen, carbon and vitamins.

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Prepared Medium Appearance

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Product Description

Organisms Ref. No Result
Pseudomonas aeruginosa ATCC 9027 Growth, green pigmented colonies
Escherichia coli ATCC 8739 Inhibited



Pancreatic digest of gelatin 20.0
Magnesium chloride 1.4
Di-potassium sulphate 10.0
Cetrimide 0.3
Agar 13.6
Total 45.3
*Adjusted/supplemented as required to meet performance requirements


Suspend 45.3g of the medium in one litre of deionised / purified water. Allow the medium to soak whilst mixing for 10 minutes. Add 10ml of glycerol and mix well. Heat with frequent agitation and boil for one minute to completely dissolve the medium. Sterilise at 121°C for 15 minutes. Cool to 45-50°C and aseptically dispense into appropriate sterile containers.