[Investigation of in vitro activities of fluconazole, itraconazole and voriconazole against clinical isolates of Blastoschizomyces capitatus (Geotrichum capitatum) by two different methods].

Blastoschizomyces capitatus is an emerging opportunistic pathogen that may lead to invasive infections particularly in neutropenic patients. In this study, the in vitro activities of fluconazole, itraconazole and voriconazole against 15 clinical B. copitatus isolates were determined by microdilution method (MD) and Etest. The isolation and identification of the isolates were done by standard mycological methods. MD tests were done in accordance with CLSI microdilution method (M27A-2). Etest was performed according to the instructions of the manufacturer (AB Biodisk, Sweden) by using RPMI-2% glucose. Since susceptibility breakpoints were not yet established for B. copitatus, only the distribution of the MIC values obtained for the tested antifungals were given. MIC values were determined after 48 h incubation and by using MIC-2 value for all the drugs tested. At 48 h, MIC90 values obtained by MD and Etest were 16 and 32 microg/ml, 0.5 and 1 microg/ml, 0.5 and 1 microg/ml for fluconazole, itraconazole and voriconazole, respectively. These results suggested that voriconazole and itraconazole had favorable activity against B. capitatus isolates. However, the activity of fluconazole remained poor and limited at least for a significant number of isolates. Percent agreement of Etest with MD method within +/-1 dilution range and at 48 hour for fluconazole, itraconazole and voriconazole were 86.7%, 80% and 73.3%, respectively, suggesting a higher agreement of the two methods for fluconazole as compared to itraconazole and voriconazole. Etest tended to generate 1-2 fold higher MICs as compared to MD MICs for most of the isolates of this particular fungus. In conclusion, further studies are required for determination of the optimal susceptibility testing method and the MIC breakpoints for B. capitatus.