Which medias are selective?

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Multiple Choice

Which medias are selective?

Explanation:
Selective media are designed to suppress unwanted organisms while allowing particular groups to grow. MacConkey agar uses bile salts and crystal violet to inhibit Gram-positive bacteria, so it favors Gram-negative enterics and can differentiate lactose fermenters by color. CNA agar employs antibiotics like colistin and nalidixic acid to suppress Gram-negative organisms, enabling growth of Gram-positive cocci (often with blood to show hemolysis patterns). Thayer-Martin medium contains compounds that inhibit many other bacteria and fungi, creating a niche for Neisseria species. Because each of these media promotes growth of specific microbes while inhibiting others, all three are selective.

Selective media are designed to suppress unwanted organisms while allowing particular groups to grow. MacConkey agar uses bile salts and crystal violet to inhibit Gram-positive bacteria, so it favors Gram-negative enterics and can differentiate lactose fermenters by color. CNA agar employs antibiotics like colistin and nalidixic acid to suppress Gram-negative organisms, enabling growth of Gram-positive cocci (often with blood to show hemolysis patterns). Thayer-Martin medium contains compounds that inhibit many other bacteria and fungi, creating a niche for Neisseria species. Because each of these media promotes growth of specific microbes while inhibiting others, all three are selective.

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