Cetrimide Broth

Pseudomonas aeruginosa is characterized by the production of pyocyanin (a blue-green water soluble non-cluorescent, phenazine pigment) which is stimulated by the inclusion of magnesium chloride and potassium sulfate in the broth.

Cetrimide (N-cetyl-NNN-trimethylammonium bromise) is added to inhibit bacteria other than Pseudomonas aerginosa. Its action as a quaternary ammonium cationic detergent causes nitrogen and phosphorous to be released from bacterial cells other than Pseudomonas aeruginosa.