1-3mm round, smooth, convex,glistening, opaque,entire edge, butyrous (butter like) consistency.
- aureus: may be yellow and have small zone of beta hemolysis.
- epidermidis: white colonies, usually nonhemolytic.
- saprophyticus: often pigmented - yellow, orange, tan
- MSA: is selective & differential media:
- aureus: ferments manitol, so colonies will change from red to yellow
- others staphs: Do NOT ferment manitol, so colonies stay red.