Question

MacConkey agar is an example of a medium that is used for which of the following purposes?

1) Selective isolation of gram-negative bacteria
2) Selective isolation of gram-positive bacteria
3) Selective isolation of both gram-negative and gram-positive bacteria
4) Selective isolation of fungi

Answer 1

MacConkey agar is used for the selective isolation of gram-negative bacteria.

Step-by-step explanation:

MacConkey agar is an example of a medium that is used for selective isolation of gram-negative bacteria. It contains bile salts and crystal violet, which inhibit the growth of many gram-positive bacteria and favor the growth of gram-negative bacteria, particularly the Enterobacteriaceae. These species are commonly found in the intestine and are adapted to the presence of bile salts.