Question

Contains Mannitol and pH indicator, Phenol Red, which allow for the distinction between Gram Positive (+) microorganisms that can ferment Mannitol, and those that cannot?

Answer 1

Mannitol Salt Agar (MSA) is a selective medium used in microbiology to differentiate between gram-positive microorganisms that can ferment mannitol and those that cannot.

Step-by-step explanation:

Mannitol Salt Agar (MSA) is a selective medium used in microbiology to differentiate between gram-positive microorganisms that can ferment mannitol and those that cannot. MSA contains mannitol, a fermentable sugar alcohol, and a pH indicator called phenol red. The high concentration of salt in MSA inhibits the growth of bacteria susceptible to osmotic stress. If a microorganism can ferment mannitol, it will produce acids, causing the pH of the medium to drop and the phenol red indicator to change from red to yellow. This color change allows for the distinction between mannitol-fermenting Staphylococcus aureus and other non-mannitol-fermenting bacteria.

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