Table 1. Mechanisms of resistance to clinically relevant classes of antifungal drugs.

Drug class	Examples of clinically used drugs	Mechanism of action	Target	Mechanism of acquired resistance	Species with intrinsic or high rates of resistance
Azole	Fluconazole, voriconazole, posaconazole	Inhibition of ergosterol biosynthesis	Lanosterol 14α-demethylase (Erg11 or Cyp51 in other organisms)	Increased efflux pump activity, ERG11 mutations, CYP51 promoter mutations	Candida glabrata, Candida krusei, Candida auris
Echinocandins	Caspofungin, micafungin, anidulafungin	Inhibition of β-1,3-glucan synthase	β-1,3-glucan synthase (Fks)	Mutations in hot-spot regions of FKS mutations	Cryptococcus spp. Fusarium spp.
Polyene	Amphotericin B,	Ergosterol sequestration	Ergosterol	Decreased membrane ergosterol, ERG mutations	Candida auris, Aspergillus terreus