Penicillin and Pimaricin Pseudomonas Agar Base (PP Pseudomonas Agar Base) is recommended for selective isolation of Pseudomonas species on addition of supplements.The medium contains Penicillin and PP Pseudomonas Selective Supplement II which contains Pimaricin (natamycin) to the medium helps in the selective isolation of Pseudomonas, thereby inhibiting the accompanying flora. Potassium sulphate and magnesium chloride serves to enhance pigment production.Pseudomonas fluorescens and Pseudomonas aeruginosa produce greenish yellow coloured colonies.