rough colony

Smooth to rough colonies after 7 or more days of incubation.

The rough colonies show a scotochromogenic yellow colour, which intensifies after exposure to light.

Large, eugonic, buff coloured and rough colonies (Löwenstein-Jensen medium at 30 C).

Pseudomonas aeruginosa: pink, flat, rough colonies.

Microscopic appearance shows gram positive rods with both smooth and rough colony types and further spore staining technique may be utilized to determine spore shape and position.