What is an inhibitor in microbial media?

An inhibitor in microbial media is a chemical that prevents the growth of certain bacteria. In the context of microbiology, inhibitors are intentionally incorporated into media to control the growth of specific organisms, allowing researchers to selectively cultivate or study particular bacterial species. For example, selective media often contains inhibitors that suppress the growth of unwanted bacteria, thereby enriching the desired population for analysis. This selective pressure can be critical in isolating pathogens from mixed cultures or when examining complex microbial communities.

In distinction to the other answer choices, which describe different components of microbial media, the role of an inhibitor is specifically to limit bacterial growth rather than to enhance it, visualize it, or provide nutrients.