This is a selective medium for the isolation of Pseudomonas spp. primarily in food, water and environmental samples. Pseudomonas agar base is on Kings A medium which uses magnesium and potassium salts to enhance pigment production.

The gelatine peptone and acid hydrolysed casein acts as a nitrogen, vitamins, and carbon source. Magnesium chloride and potassium sulphate promotes production of pyocyanin.

The medium can be made selective for P. aeruginosa by the addition of Pseudomonas CN Supplement (MED1530). Alternatively, the medium can be made selective for Pseudomonas spp. generally by the addition of Pseudomonas CFC Selective Supplement (MED1558).

The presence of blue/green or brown pigmentation or fluorescence is indicative of presumptive Pseudomonas spp. It should be noted however that further testing must be carried out to confirm the full identity of the organism.

Preparation

Suspend 48.4g of the medium in 1L of deionised / purified water. Add 10mL of glycerol. Allow the medium to soak whilst mixing for 10 minutes. Heat with frequent agitation and boil for one minute to completely dissolve the medium. Sterilise at 121°C for 15 minutes. Cool to 45-50°C and aseptically add the required numbers of vials of either Pseudomonas CN Supplement (MED1530) or Pseudomonas CFC Selective Supplement (MED1558). Mix well and dispense into appropriate sterile containers.