Consider a culture medium on which only gram-positive organisms such as Staphylococcus aureus colonies can grow due to an elevated NaCl level.A yellow halo surrounds the growth,indicating the bacterium fermented a sugar in the medium,decreasing the pH as a result and changing the color of a pH indicator chemical.This type of medium would be referred to as a(n)
A)selective medium.
B)differential medium.
C)enrichment culture.
D)selective and differential medium.
E)differential and enrichment culture.

Question

Quizplus · Accepted Answer

This medium is both selective, as it only allows for the growth of gram-positive organisms and differential, as it allows for the differentiation of organisms that can ferment sugars and change pH. Therefore, the correct choice is D, selective and differential medium.

Consider a Culture Medium on Which Only Gram-Positive Organisms Such