Rare modification in the ergosterol biosynthesis pathway leads to amphotericin B resistance in Candida auris clinical isolates

We determined amphotericin B (AmB) susceptibility and sequenced key genes of the ergosterol biosynthesis pathway implicated in AmB resistance ( ERG2, ERG3, ERG6, ERG11 ) of 321 clinical isolates of Candida auris . In antifungal susceptibility testing, 19 (5.9%) isolates were categorized as AmB-resistant (MIC ≥2 mg/l). Only one AmB-resistant isolate presented a unique non-wild-type ERG6 genotype that was confirmed to confer amphotericin B resistance (MIC >32 mg/l) when introduced into a susceptible strain (MIC = 0.5 mg/l).