Antimicrobial susceptibility testing of dematiaceous filamentous fungi: Effect of medium composition at different temperatures and times of reading

We examined the effects of the composition of five media on the MICs of three antifungal agents (amphotericin B, flucytosine and ketoconazole) against 24 dematiaceous fungi at different temperatures and times of reading. Media studied were RPMI 1640, tryptic soy broth (TSB), yeast nitrogen broth (YNB), casein-yeast-glucose broth (CYG) and high-resolution medium (NR). The degree of reproducibility was determined with ketoconazole and 5-fluorocytosine and the media TSB and RPMI showed the best results with ketoconazole, while the best results for flucytosine were in CYG. Reproducibility was higher at 25 degrees than at 30 degreesC. The media and incubation time were shown to have a significant influence on the MICs of the three antifungals, but there were no interactions between these variables and temperature, except in the case of ketoconazole, where media-temperature and media-incubation time interactions were significant. There were noteworthy differences between the MICs obtained with the different media.