KM0031 Mannitol Salt Agar is a selective medium for the isolation of Staphylococcus aureus from clinical samples, food, cosmetics and water samples. Chapman showed that adding a higher level of sodium chloride to Mannitol Salt Agar allowed for the recovery of pathogenic staphylococci and inhibits most organisms. Coagulase positive staphylococci (e.g., S. aureus) produce yellow colonies and a surrounding yellow medium while coagulase negative staphylococci produce red colonies and no colour change of the phenol red indicator.
The medium conforms to the requirements of the Harmonised EP/USP/JP, is recommended as a primary isolation media by the UK Standards for Microbiology Investigations and tested in accordance with ISO 11133:2014 and Clinical and Laboratory Standards Institute. This medium is also included in the Bacteriological Analytical Manual for cosmetics testing.