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

Med Mycol. 2023 Apr 29;61(5):myad045. doi: 10.1093/mmy/myad045.

Abstract

We compared the antifungal susceptibility of 92 Mucorales isolates obtained by visual inspection and spectrophotometric readings following EUCAST (European Committee on Antimicrobial Susceptibility Testing) testing. Amphotericin B minimum inhibitory concentrations (MICs) were up to 1 mg/l against most isolates and variable among species, except for Cunninghamella bertholletiae. Posaconazole MICs against most isolates were up to 1 mg/l and high against Mucor circinelloides, some Rhizopus arrhizus, and Rhizopus microsporus. Isavuconazole MICs ranged between 1 and 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.

Keywords: EUCAST; MIC; Mucorales; isavuconazole; spectrophotometric readings.

Plain language summary

The agreement between minimum inhibitory concentration (MIC) values obtained by visual inspection or spectrophotometric readings was moderate and higher when the ≥90% fungal growth inhibition endpoint was chosen. Isavuconazole presented higher MICs than posaconazole, regardless of the inhibition endpoint used.

MeSH terms

  • Amphotericin B / pharmacology
  • Animals
  • Antifungal Agents / pharmacology
  • Antifungal Agents / therapeutic use
  • Itraconazole*
  • Microbial Sensitivity Tests / veterinary
  • Mucorales*

Substances

  • Itraconazole
  • Amphotericin B
  • posaconazole
  • isavuconazole
  • Antifungal Agents