Cetrimide – MacConkey Agar Plate

Cetrimide – MacConkey Agar Plate is a combination medium for the selective isolation and differentiation of bacteria in clinical, food, dairy, water and pharmaceutical products. The Cetrimide Agar element promotes the selective isolation of Pseudomonas aeruginosa from other bacteria and can be used for presumptive identification due to production of characteristic pigmentation and fluorescence. MacConkey Agar allows for the detection and differentiation of Gram-negative enteric bacteria as lactose fermenters and non-lactose fermenters.
Cetrimide is a selective agent, and inhibits most of the microorganisms, but P. aeruginosa can grow in the presence of it and produce characteristic colonies. Magnesium chloride and potassium sulfate promote pigment production, and gelatin peptone is a source of nutrients required for growth of the microorganism. Peptone, tryptone and gelatin peptone in MacConkey Agar yield a nitrogenous and a carbonaceous source while lactose is the fermentable carbohydrate.
Bile salts and crystal violet suppress the growth of Gram-positive bacteria while neutral red is a pH indicator that distinguishes lactose fermenting bacteria on the basis of colony colour. P. aeruginosa also produces blue, blue-green or non-pigmented colonies, only fluorescent and blue-green colonies considered to be presumptive positive. Further testing with biochemical or serological tests may be performed for confirmation.

Designed for the selective isolation of Pseudomonas aeruginosa and the detection and differentiation of Gram-negative enteric bacteria from clinical, food, dairy, water and pharmaceutical samples.