Question

Contains Eosin and Methylene Blue, which inhibits the growth of Gram Positive (+) microorganisms, therefore selective for Gram Negative (-) microorganisms?

1) True
2) False

Answer 1

EMB agar containing eosin and methylene blue is selective for gram-negative microorganisms.

Step-by-step explanation:

True. The medium described in the question is EMB agar, which contains eosin and methylene blue as indicator dyes. These dyes inhibit the growth of gram-positive microorganisms, making the medium selective for gram-negative microorganisms. Lactose fermenters on EMB agar form metallic green or deep purple colonies, while nonlactose fermenters form colorless colonies. This selective property allows for the identification of different types of bacteria based on their ability to ferment lactose.