For identification of phosphatase positive Staphylococcus aureus
Phenolphthalein Phosphate Agar is prepared by using Veg peptone and Veg extract in place of peptic digest of animal tissue and Beef extract which make the medium free of BSE/TSE risks. Phenolphthalein Phosphate Agar (Veg) is the modification of Phenolphthalein Phosphate Agar which is used for the identification of phosphatase positive colonies of Staphylococccus aureus which is a coagulase positive pathogenic strains. This medium contains Veg peptone and Veg extract supply the nitrogenous compounds, growth factors and trace ingredients essential for the growth of Staphylococcus aureus. Sodium phenolphthalein phosphate serves as a substrate for the phosphatase enzyme. Sodium chloride maintains osmotic equilibrium. Phosphatase production is determined by the liberation of phenolphthalein which is indicated by the change in colour of the medium. Colour change is indicated by addition of alkali to this medium, the liberated phenolphthalein gives bright pink - red colouration.