Mannitol Salt Agar Medium is a medium used for selective isolation of S. aureus.

Formula:

Pancreatic  digest  of  casein...5.0 
Peptic  digest  of  animal 
tissue..............................5.0
Beef  extract......................1.0 
D-Mannito.......................10.0
Sodium  chloride................75.0
Agar..............................15.0
Phenol red......................0.025
Final pH 7.4±0.2 at 25℃            
Directions:

Suspend 112.5g of the medium in one liter of distilled water or deionized water, mix thoroughly, sterilize in an autoclave at 121℃ for 15 minutes after dispensing.