Background: Section Flavi within genus Aspergillus includes a large number of species that may behave as opportunistic pathogens in humans or animals and/or may produce mycotoxins. Morphological similarities between Flavi section members make precise identification difficult. In this study, we present data on antifungal susceptibility profile of molecularly characterized French clinical isolates of Flavi section.
Materials/methods: Sixty-one isolates, phenotypically identified as A. flavus, were included in the study. These clinical isolates were recovered over a 15-year period (2001-2015). For all isolates, specific identification was confirmed by sequencing a part of the β-tubulin and calmodulin genes. The isolates were first screened for their susceptibility to azoles antifungal agents by using 3-sectors agar plates containing itraconazole, voriconazole and a drug-free control. Susceptibility to 8 antifungal drugs was further determined by using EUCAST reference microdilution broth technique.
Results: Out of 61 isolates, molecular analysis of the partial β-tubulin and calmodulin sequences showed that 59 isolates were A. flavus sensu stricto and one isolate each was A. parasiticus and A. nomius. One isolate was azole-resistant by the screening test. The geometric mean MIC values (range) of amphotericin B, itraconazole, voriconazole, posaconazole, isavuconazole, caspofungin, micafungin, and anidulafungin were 3.32 (1-16), 0.36 (0.125-2), 1.02 (0.5-8), 0.4 (0.125-1), 1.26 (0.25- 8), 0.066 (0.03-0.125), 0.016 (0,016-0,03), 0,017 (0,016-0,03) µg/mL for the A. flavus sensu stricto. For A. parasiticus and A. nomius, MICs were in the same range. Only one A. flavus sensu stricto isolate had voriconazole and isavuconazole MICs at 8 µg/mL.
Conclusions: Antifungal susceptibility to 8 drugs was determined on a large collection of clinical isolates belonging to Aspergillus Flavi section. Most of the isolates were identified as A. flavus sensu stricto and most of them were susceptible to antifungal drugs. Nevertheless, the occurrence of one resistant isolate highlights the need for susceptibility testing for any Aspergillus section.
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Full conference title:
- ECCMID 30th (2020)