Cetrimide agar

Cetrimide agar is a type of agar used for the selective isolation of the gram-negative bacterium, Pseudomonas aeruginosa. As the name suggests, it contains cetrimide, which is the selective agent against alternate microbial flora. Cetrimide also enhances the production of Pseudomonas pigments such as pyocyanin and fluorescein, which show a characteristic blue-green and yellow-green colour, respectively.