Which of the following best describes the mechanism of action of antifungal drugs such as miconazole and amphotericin B?

• A. They disrupt the synthesis of ergosterol in fungal cell membranes.
• B. They interfere with protein synthesis by binding to ribosomes.
• C. They inhibit peptidoglycan synthesis in bacterial cell walls.
• D. They block DNA replication by inhibiting DNA gyrase.

Answer: (A)

Verified step by step guidance

1. Step 1: Understand the target of antifungal drugs like miconazole and amphotericin B. These drugs specifically target components unique to fungal cells, particularly the fungal cell membrane.
2. Step 2: Recall that fungal cell membranes contain ergosterol, a sterol molecule similar to cholesterol in animal cells, which is essential for maintaining membrane integrity and function.
3. Step 3: Recognize that miconazole works by inhibiting the synthesis of ergosterol, thereby disrupting the fungal cell membrane and leading to increased membrane permeability and cell death.
4. Step 4: Understand that amphotericin B binds directly to ergosterol in the fungal membrane, creating pores that cause leakage of cellular contents, which also results in fungal cell death.
5. Step 5: Compare these mechanisms to the other options: protein synthesis inhibition (ribosomes), peptidoglycan synthesis inhibition (bacterial cell walls), and DNA replication inhibition (DNA gyrase) are mechanisms of action for other types of antimicrobial agents, not antifungals like miconazole and amphotericin B.