Antifungal susceptibility testing of clinical yeast isolates and algae of the genus Prototheca to fluconazole and itraconazole by means of the Etest

Preliminary own results suggest, that the Etest(R) (produced by AB BIODISK, Solna, Sweden) performed on casitone medium meets the requirements of a routine test of yeast susceptibility to fluconazole and itraconazole. Testing of 46 clinical yeast isolates, of 5 strains of Exophiala dermatitidis and 4 strains of algae of the genus Prototheca revealed species-, genus- and strain-specific variations of the susceptibility to fluconazole and itraconazole. Candida glabrata was less susceptible to both triazoles than the other Candida species with exception of Candida krusei. Exophiala dermatitidis was highly susceptible to itraconazole. Prototheca wickerhamii and P. zopfii were resistant to both triazoles. - Casitone medium is most appropriate for the determination of susceptibility to fluconazole and itraconazole by the Etest. - The results of the Etest were comparable with those of a breakpoint test (microdilution method).