Agar is a jelly-like substance, obtained from red algae, used heavily as a solid medium for growing various microbes. Many specific formulations are available because some microbes prefer certain environmental conditions over others.
Pseudomonas Cetrimide Agar is used for the selective isolation and identification of Pseudomonas aeruginosa.
Preparation: Suspend 45.3 g in 1 litre of demin water by heating in a boiling water bath or in a current of steam; add 10 min of glycerol (MERCK, Cat. No. 1.04094); autoclave (15 min. at 121oC); pour to plates.
pH: 7.2 ± 0.2 at 25oC.
Typical Composition (g/litre): Peptone from gelatin 20.0; Magnesium chloride 1.4; Potassium sulfate 10.0; N-Cetyl-N,N,N-trimethylammonium bromide (cetrimide) 0.3; Agar-agar 13.6