Which of the following statements about selective media is correct?

• A. Selective media can also be differential, allowing for both selection and differentiation of microorganisms.
• B. Selective media only support the growth of all microorganisms equally.
• C. Selective media cannot be differential.
• D. Selective media are used exclusively for viral cultures.

Answer: (A)

Verified step by step guidance

1. Understand the definition of selective media: Selective media are designed to favor the growth of certain microorganisms while inhibiting others, allowing for the isolation of specific types of bacteria.
2. Recognize what differential media are: Differential media contain indicators that allow you to distinguish between different types of microorganisms based on their biological characteristics, such as color changes due to metabolic activity.
3. Analyze the relationship between selective and differential media: Some media combine both properties, meaning they can select for certain microbes and also differentiate between them based on their biochemical traits.
4. Evaluate each statement in the problem: For example, the statement that selective media only support the growth of all microorganisms equally contradicts the definition of selective media, which inhibit some organisms.
5. Conclude that the correct statement is the one acknowledging that selective media can also be differential, as this reflects the dual function of some specialized media used in microbiology.