When grown on mannitol salt agar some species of Micrococcus (Micrococcus is a normal flora of human skin, mucosa, and oropharynx), such as M. luteus (yellow) can produce yellow colonies. ... They can ferment mannitol and produce lactic acid, producing yellow-colored colonies on MSA.

What can Micrococcus luteus ferment?

luteus oxidizes carbon compounds such as glucose to carbon dioxide and water. Hence no acid is found and glucose and the fermentation tests appear negative. The primary natural habitat is the mammalian skin; the secondary habitat is meat and dairy products, soil and water.

What bacteria can ferment mannitol?

Most pathogenic staphylococci, such as Staphylococcus aureus, will ferment mannitol. Most non-pathogenic staphylococci will not ferment mannitol. The Staphylococcus aureus ferments mannitol and turns the medium yellow. The Serratia marcescens does not grow because of the high salt content.