In vitroactivities of posaconazole, ravuconazole, terbinafine, itraconazole and fluconazole against dermatophyte, yeast and non-dermatophyte species

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Abstract
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 µg/ml for dermatophytes, 0.5 and 0.25 µg/ml for yeasts, and >4 and 8 µg/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 µg/ml), ravuconazole (0.015–8.0/0.015–1.0/0.015–1.0 µg/ml), itraconazole (0.015– >8.0/0.015–0.5/0.015–8.0 µg/ml), fluconazole (0.125– >64.0/4.0– >64.0/0.5–64.0 µg/ml) and terbinafine (0.003– >2.0/0.007–2.0/0.007– >2.0 µg/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.