Amphotericin B, itraconazole, posaconazole, and isavuconazole MICs against clinical Mucorales isolates obtained by visual inspection and spectrophotometric reading according to the EUCAST 9.4 procedure.

We compared the antifungal susceptibility of 92 Mucorales isolates obtained by visual inspection and spectrophotometric readings following EUCAST testing. Amphotericin B MICs were up to 1 mg/L against most isolates and variable among species, except for C. bertholletiae. Posaconazole MICs against most isolates were up to 1 mg/L and high against M. circinelloides, some R. arrizhus, and R. microsporus. Isavuconazole MICs ranged between 1-8 mg/L but were invariably >8 mg/L against M. circinelloides and C. bertholletiae. The agreement between MICs obtained by visual endpoint or spectrophotometric readings was moderate and higher when using the ≥ 90% fungal growth inhibition endpoint.