Intra- and inter-laboratory comparison of mDixon and FastFung broths for Malassezia antifungal susceptibility testing

Mycoses. 2021 Jul;64(7):716-720. doi: 10.1111/myc.13270. Epub 2021 May 20.

Abstract

Background: Malassezia spp. antifungal susceptibility testing (AFST) capacities are limited by the lack of efficient and standardised AFST procedure, mainly because of the fastidious cultivation of these yeast.

Objectives: This study aimed to compare the FastFung broth (FFB) to modified Dixon broth (mDIXB) for the in vitro AFST of Malassezia spp. Fluconazole, ketoconazole, voriconazole and terbinafine MICs against a 19 Malassezia strains, including 6 M furfur, 4 M pachydermatis, 5 M sympodialis and 4 M slooffiae.

Methods: The essential agreement (EA) between the two assays, and the intra- and inter-laboratory agreement of each assay were assessed.

Results: The MIC data obtained in our study were comparable to those reported in the literature. FFB showed to enhance Malassezia growth and displayed 100% (±2-fold dilution) EAs demonstrating similar performances to mDIXB. In addition, the MIC data obtained by using the FFB were reproducible between laboratories with EAs ranging from 94.7% to 100%.

Conclusions: Therefore, FFB is a suitable alternative to mDXB for Malassezia spp. AFST.

Keywords: Malassezia; antifungal susceptibility; intra and inter-laboratory testing.

MeSH terms

  • Antifungal Agents / pharmacology
  • Dermatomycoses / drug therapy
  • Humans
  • Laboratories
  • Malassezia / drug effects
  • Malassezia / growth & development*
  • Microbial Sensitivity Tests / methods

Substances

  • Antifungal Agents