Is peptone part of a selective medium?

Peptone is not typically considered a selective agent in a selective medium; rather, it serves as a nutrient source that supports the growth of a wide variety of microorganisms. Selective media usually contain specific inhibitors or conditions that favor the growth of certain organisms while suppressing others. However, peptone can be included in selective media to provide essential nutrients for the target organisms. Thus, its primary role is to enhance growth rather than to select for specific microbial populations.