This is a Provisional monograph.

Modified King's broth A (Drake, 1966) was originally used for the isolation of pseudomonads. It contained additional potassium sulfate and magnesium chloride to enhance the pigment production of Pseudomonas aeruginosa. Goto and Enomoto (1970) demonstrated the selective agents cetrimide and nalidixic acid as suitable for the isolation of Pseudomonas aeruginosa. Confirmation of presumptive colonies is by subculture to milk agar for demonstration of casein hydrolysis (Brown and Scott Foster, 1970).

Add the ingredients, except the cetrimide and nalidixic acid, to the water and boil to dissolve. Dispense into suitable containers and autoclave at 121°C for 15 min. The medium should be cooled to 50°C and 1 mL of a filter-sterilised solution of 2% cetrimide and 1 mL of a 0.15% filter-sterilised solution of sodium nalidixate added per 100 mL of medium.