Three different strains of Pseudomonas aeruginosa inoculated on the surface of cetrimide agar. Cultivation 48 hours at 37°C.

P.aeruginosa colonies on cetrimide agar may appear pigmented blue, blue-green or non-pigmented. Colonies exhibiting
fluorescence at 250nm and a blue green pigmentation are considered as presumptive positive P.aeruginosa isolates.