Mannitol Salt Agar is used for selective isolation and enumeration of staphylococci from clinical or non-clinical samples. Peptones and beef extract provide essential growth factors such as nitrates, carbon, and trace elements. The high concentration of sodium chloride results in partial or total inhibition of the growth of all bacteria, except staphylococci. Mannitol fermentation, which appears as a color change of the phenol red indicator, helps to differentiate staphylococcal species. Inoculate by spreading the sample on the surface of the medium. Incubate for 24-48 hours at 37°C under aerobic conditions. Observe the colonies and consult the table.