Ian Jesús Cambronero Ortiz, Daniela Jaikel Víquez, Norma Gross Martínez
Introduction: Aspergillosis affects mainly immunosuppressed patients, especially those with neutropenia. A decreased susceptibility of antifungals used in the treatment of this disease has been reported in the last decade. At present, in Costa Rica there is a lack of studies concerning the antifungal activity of clinical Aspergillus isolates. Thus, the purpose of the present investigation was to determine the in vitro susceptibility patterns of clinical Aspergillus fumigatus, A. flavus, A. niger, A. terreus and A. versicolor. Methods: The susceptibility of 42 Aspergillus spp. to amphotericin B, itraconazole and voriconazole was evaluated using the Clinical and Laboratory Standards Institute broth microdilution M38-A guideline for filamentous fungi. Results: The mean minimal inhibitory concentration (MIC) for A. fumigatus was 1,64 µg mL-1 for amphotericin B, 1,38 µg mL-1 for itraconazole and 3.52 µg mL-1 for voriconazole, and 33,3 % of the isolates were resistant to voriconazole. For the other species tested, the mean MIC was 7,19 µg mL-1 for amphotericin B, 0,46 µg mL-1 for itraconazole and 1,58 µg mL-1 for voriconazole. Conclusions: MIC values for amphotericin B and itraconazole of most A. fumigatus isolates were comparable to those of wild-type strains. However, a significant percentage of the isolates were resistant to voriconazole, the first line treatment for aspergillosis. Further, A. flavus, A. niger, A. terreus and A. versicolor demonstrated high MIC values for amphotericin B; thus, it is recommended to performed susceptibility testing in these cases if there is a poor response to therapy.