Medline ® Abstract for Reference 36
of 'Invasive Malassezia infections'
Antifungal susceptibility testing of Malassezia yeast: comparison of two different methodologies.
Rojas FD, Córdoba SB, de LosÁngeles Sosa M, Zalazar LC, Fernández MS, Cattana ME, Alegre LR, Carrillo-Muñoz AJ, Giusiano GE
Mycoses. 2017;60(2):104. Epub 2016 Sep 14.
All Malassezia species are lipophilic; thus, modifications are required in susceptibility testing methods to ensure their growth. Antifungal susceptibility of Malassezia species using agar and broth dilution methods has been studied. Currently, few tests using disc diffusion methods are being performed. The aim was to evaluate the in vitro susceptibility of Malassezia yeast against antifungal agents using broth microdilution and disc diffusion methods, then to compare both methodologies. Fifty Malassezia isolates were studied. Microdilution method was performed as described in reference document and agar diffusion test was performed using antifungal tablets and discs. To support growth, culture media were supplemented. To correlate methods, linear regression analysis and categorical agreement was determined. The strongest linear association was observed for fluconazole and miconazole. The highest agreement between both methods was observed for itraconazole and voriconazole and the lowest for amphotericin B and fluconazole. Although modifications made to disc diffusion method allowed to obtain susceptibility data for Malassezia yeast, variables cannot be associated through a linear correlation model, indicating that inhibition zone values cannot predict MICvalue. According to the results, disc diffusion assay may not represent an alternative to determine antifungal susceptibility of Malassezia yeast.
Departamento de Micología, Instituto de Medicina Regional, Universidad Nacional del Nordeste, Resistencia, Chaco, Argentina.