In vitro activity of amphotericin B, itraconazole and voriconazole against 20 species of Aspergillus using the Sensititre microdilution method

The in vitro activity of antifungal agents against Aspergillus has been recently investigated. We studied the susceptibility to amphotericin B, itraconazole and voriconazole of 68 strains belonging to 20 different Aspergillus species. The minimum inhibitory concentrations (MICs) for 10 strains of A. fumigatus, 9 A. flavus, 8 A. niger, 5 A. tamarii, 5 A. versicolor, 4 A. terreus, 3 A. glaucus, 3 A. ochraceus, 3 A. oryzae, 2 A. candidus, 2 A. chevalieri, 2 A. rubrobrunneus, 2 A. sclerotiorum, 2 A. sydowii, 2 A. unguis, 2 A. ustus, 1 A. clavatus, 1 A. nidulans, 1 A. pseudofischeri y 1 A. reptans, were determined using the Sensititre Yeast One microdilution method. Voriconazole was more active in vitro than amphotericin B and itraconazole, with 95.6% (65/68) of strains exhibiting MICs of < or = 2 mg/l. A. flavus, A. versicolor, A. terreus, A. ochraceus, A. sclerotiorum, A. ustus and A. reptans species presented reduced susceptibility to amphotericin B (MIC > or = 2 mg/l); A. niger, A. versicolor, A. sclerotiorum and A. ustus showed in vitro resistance to itraconazole (MIC > or = 1 mg/l); and A. sclerotiorum and A. ustus displayed poor susceptibility to voriconazole (MIC > or = 2 mg/l). The susceptibility of Aspergillus species to itraconazole and voriconazole was generally good; nevertheless, susceptibility to amphotericin B was low. These results suggest that Aspergillus susceptibility testing to this antifungal agent would be advisable to guide treatment.