Can voriconazole gradient diffusion testing results be extrapolated to isavuconazole and posaconazole in Aspergillus spp.? Comparative analysis with CLSI broth microdilution and cyp51A gene sequencing

Key Points

• This research aims to determine if voriconazole gradient diffusion testing can reliably predict results for isavuconazole and posaconazole in Aspergillus species.
• Compared voriconazole gradient diffusion results to CLSI broth microdilution results and cyp51A sequencing for two species: Aspergillus fumigatus and Aspergillus terreus.
• Assessed agreement with CLSI results at 48 hours for various azole-species combinations.
• Voriconazole-posaconazole extrapolation was reliable across both species.
• Voriconazole-isavuconazole extrapolation varied depending on the species.
• Gradient diffusion testing sometimes missed resistance detection in cyp51A mutant isolates, raising concerns of false susceptibilities.