In vitro activities of posaconazole, ravuconazole, terbinafine, itraconazole and fluconazole against dermatophyte, yeast and non-dermatophyte species.

The in vitro activities of two new triazole antifungal agents with broad-spectrum antifungal activity, posaconazole and ravuconazole, were compared with those of three well-established antifungal agents, terbinafine, itraconazole and fluconazole, against 184 clinical isolates. These included 129 dermatophyte isolates (twelve species), 25 yeast isolates (five species) and 28 non-dermatophyte isolates (nine species). In vitro testing was conducted using microdilution plates with RPMI 1640 and National Committee for Clinical Laboratory Standards (NCCLS) guidelines (M27-38P) were followed, except for the preparation of the dermatophyte inoculum. Both posaconazole and ravuconazole showed similar broad-spectrum activity against dermatophyte, yeast and non-dermatophyte species. Mean inhibitory concentrations (MIC) at which 90% [MIC90] of the isolates were inhibited by posaconazole and ravuconazole were 0.25 and 0.5 microg/ml for dermatophytes, 0.5 and 0.25 microg/ml for yeasts, and >4 and 8 microg/ml for non-dermatophytes. The MIC ranges against Trichophyton (six species), Microsporum (five species) and Epidermophyton flocossum were: posaconazole (0.007-1.0/0.007-0.25/0.007-1.0 microg/ml), ravuconazole (0.015-8.0/0.015-1.0/0.015-1.0 microg/ml), itraconazole (0.015- >8.0/0.015-0.5/ 0.015-8.0 microg/ml), fluconazole (0.125- >64.0/4.0 >64.0/0.5-64.0 microg/ml) and terbinafine (0.003 >2.0/0.007-2.0/0.007 >2.0 microg/ml). Overall ranking of the antifungal activity of the five antifungal agents was: terbinafine > posaconazole > ravuconazole > itraconazole > fluconazole, for dermatophytes; ravuconazole > posaconazole > itraconazole > fluconazole > terbinafine, against yeasts; and posaconazole > ravuconazole > terbinafine > itraconazole > fluconazole, for non-dermatophytes.