Print page Print page
Switch language
The Capital Region of Denmark - a part of Copenhagen University Hospital

EUCAST Determination of Olorofim (F901318) Susceptibility of Mold Species, Method Validation, and MICs

Research output: Contribution to journalJournal articleResearchpeer-review


  1. ECMM CandiReg-A ready to use platform for outbreaks and epidemiological studies

    Research output: Contribution to journalJournal articleResearchpeer-review

  2. EUCAST Reference Testing of Rezafungin Susceptibility and Impact of Choice of Plastic Plates

    Research output: Contribution to journalJournal articleResearchpeer-review

View graph of relations

Olorofim is a novel antifungal agent with in vitro activity against Aspergillus and some other molds. Here, we addressed technical aspects for EUCAST olorofim testing and generated contemporary MIC data. EUCAST E.Def 9.3.1 testing was performed comparing two plate preparation methods (serial dilution in medium [serial plates] versus predilution in DMSO [ISO plates]), two lots of olorofim, visual (visual-MIC) versus spectrophotometer (spec-MIC) reading, and four polystyrene plates using 34 to 53 Aspergillus isolates from five genera. Subsequently, olorofim MICs were compared to itraconazole, voriconazole, posaconazole, and amphotericin B MICs for 298 clinical mold isolates (2016 to 2017). Wild-type upper limits (WT-UL) were determined following EUCAST principles for epidemiologic cutoff value (ECOFF) setting. Olorofim median MICs comparing serial plates and ISO plates were identical (25/36 [69%]) or one dilution apart (11/36 [31%]). Interperson agreement for visual-MICs was 92% to 94%/100% for ≤1/≤2 dilutions, respectively. The visual-MIC values across tested microtiter plates and olorofim lots revealed only discrete differences (≤1 dilution lower for treated plates). No single spec-MIC criterion was applicable to all species. Olorofim MICs were low against 275 Aspergillus species isolates (modal MIC, 0.06 mg/liter; MIC range, < 0.004 to 0.25 mg/liter) and three dermatophytes (MICs 0.03 to 0.06 mg/liter). MICs against Fusarium were diverse, with full inhibition of F. proliferatum (MIC, 0.016), 50% growth inhibition of Fusarium solani at 1 to 2 mg/liter, and no inhibition of F. dimerum Olorofim displayed potent in vitro activity against most mold isolates and was associated with limited variation in EUCAST susceptibility testing.

Original languageEnglish
JournalAntimicrobial Agents and Chemotherapy
Issue number8
Pages (from-to)e00487-18
Publication statusPublished - Aug 2018

ID: 56273090