Question

After inoculating a mannitol salt agar with a skin swab from behind your ear, would you rather find mannitol fermentation-negative or mannitol fermentation-positive colonies on the plate?

1) mannitol fermentation-negative colonies
2) mannitol fermentation-positive colonies

Answer 1

Mannitol fermentation-positive colonies are preferred to be found on the plate inoculated with a skin swab. This indicates the presence of Staphylococcus aureus, a common skin bacterium that can ferment mannitol.

Step-by-step explanation:

After inoculating a mannitol salt agar plate with a skin swab from behind your ear, you would rather find mannitol fermentation-positive colonies on the plate.

Mannitol fermentation-positive colonies will cause a color change from red to yellow in the medium. This indicates that the bacteria present can ferment mannitol, which is a characteristic of Staphylococcus aureus, a common skin bacterium.