Salt agar is characterized by a high concentration of sodium chloride. This amount of chloride inhibits the growth of concomitant microflora, but does not affect the growth of Staphylococcus aureus and contributes to it's isolation from clinical material. Besides the nutritional part of the environment fully supports the development of lecithinase Staphylococcus, and they can be identified with the formation of the iridescent zone around the colonies.