Product Code TMP 021
MANNITOL SALT AGAR is used for the selective isolation and enumeration of Staphylococci species. Chapman formulated Mannitol Salt Agar to isolate staphylococci by inhibiting growth of most other bacteria with a high salt concentration. Pathogenic staphylococci, i.e. Staphylococcus aureus (coagulase test positive) is able to ferment Mannitol but other coagulase negative Staphylococcus are not. So, if that particular specimen contains S. aureus, it ferments mannitol and changes the pH of medium to acidic. As MSA contains phenol red as a pH indicator, at pH levels below 6.9, the medium is a yellow colour. But if Coagulase negative staphylococci grow, they can?t ferment mannitol, so the colour of the media around the bacterial colony does not change to yellow, it appears pink.
Note: Staphylococcus saprophyticus (coagulase negative Staphylococcus) may ferment mannitol, producing yellow halo around colonies in MSA thus resembling with S. aureus
For selective isolation of pathogenic Staphylococci.
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