Microdilution in vitro antifungal susceptibility of Exophiala dermatitidis, a systemic opportunist

Abstract

The in vitro activities of eight antifungal agents were determined against clinical (n = 63 genotype A, n = 3 genotype B) and environmental (n = 2 genotype A, n = 13 genotype B) strains of Exophiala dermatitidis. The resulting MIC(90)s for all strains (N = 81) were, in increasing order, as follows: posaconazole, 0.125 μg/ml; itraconazole, 0.25 μg/ml; voriconazole, 0.5 μg/ml; amphotericin B, 0.5 μg/ml; isavuconazole, 1 μ/ml; caspofungin, 8 μg/ml; anidulafungin, 8 μg/ml and fluconazole, 16 μg/ml. There were no significant differences in the patterns of susceptibility between genotypes A and B, environmental and clinical strains, isolates recovered from cutaneous and deep locations and strains from different geographical areas (P > 0.05). The difference in the MIC(90)s between each of these groups was not more than one dilution. The present study demonstrated that, based on in vitro activity, posaconazole and itraconazole have the highest activity against this fungus. In addition, voriconazole and the experimental broad-spectrum antifungal triazole, isavuconazole, both of which are available as intravenous preparations, have adequate activity against E. dermatitidis. However, in vivo efficacy remains to be determined.

In vitro antifungal activity of Indian liposomal amphotericin B against clinical isolates of emerging species of yeast and moulds, and its comparison with amphotericin B deoxycholate, voriconazole, itraconazole and fluconazole

“…Similar to many other studies, 29,30 VOR showed good activity against the dematiaceous fungi ( N = 27), with an MIC ≤2 mg l −1 in all the isolates tested. Fungisome TM was also effective against these fungi, with an MIC ≤1 mg l −1 in all the isolates tested, except one Phialophora verrucosum isolate.…”

In vitro activity of colistin as single agent and in combination with antifungals against filamentous fungi occurring in patients with cystic fibrosis

“…A previous study used Etest to test E. dermatitidis and found that isolates were susceptible to CAS 32 . Other studies using BDM found results similar to ours 33,34 . In agreement with Pfaller et al.…”

Molecular typing and antifungal susceptibility of Exophiala isolates from patients with cystic fibrosis

“…Most of the isolates of E. dermatitidis and E. phaeomuriformis displayed very low MICs of amphotericin B, itraconazole and voriconazole, thus, confirming previous observations from other reports (Kondori et al, 2011;Badali et al, 2011;Fothergill et al, 2009). However, in patient UCL1, 10 out of the 12 sequential isolates showed high MICs (between 4 and 16 mg ml 21 ) of voriconazole, and 11 isolates showed MICs of 2 mg ml 21 of amphotericin B.…”