A 65-year-old man with acute myeloid leukemia develops Candida tropicalis bloodstream infection. The isolate shows resistance to fluconazole but remains susceptible to micafungin. What is the mechanism of action of micafungin?
- A Inhibition of β-(1,3)-D-glucan synthase, disrupting cell wall synthesis ✓
- B Inhibition of ergosterol synthesis by binding to lanosterol 14α-demethylase
- C Binding to ergosterol and forming membrane pores causing cell lysis
- D Inhibition of squalene epoxidase blocking ergosterol biosynthesis
Correct answer: A. Inhibition of β-(1,3)-D-glucan synthase, disrupting cell wall synthesis
Explanation
Echinocandins (micafungin, caspofungin, anidulafungin) inhibit β-(1,3)-D-glucan synthase, blocking synthesis of an essential cell wall polysaccharide. They are active against most Candida species including many azole-resistant strains. Option B describes azoles, option C describes amphotericin A, and option D describes terbinafine.
Reference: Katzung & Trevor's Pharmacology: Examination and Board Review, 13th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.