Antifungal susceptibility of ocular fungal pathogens recovered from around the world against itraconazole, voriconazole, amphotericin B, and caspofungin

Abstract

Although fungal infections of the eye are rare, they create an intractable clinical problem in ophthalmology because of the limited number of intravitreal and systemic therapeutic options. In this investigation, the in vitro efficacies of itraconazole (ITR), voriconazole (VOR), amphotericin B (AMB), and caspofungin (CAS) against 29 globally-collected ocular fungal isolates were assessed, following the standards that are outlined in the Clinical and Laboratory Standards Institute (CLSI) M38-A2 document. AMB [Geometric Mean (GM) MIC (Minimum Inhibitory Concentration): 0.49 μg/ml] was the most active drug, followed by VOR, CAS, and ITR (GM MICs: 0.52, 1.07, and 2.86 μg/ml, respectively). For the Exophiala strains (n = 8), VOR was the most active drug, followed by AMB, ITR, and CAS (GM MICS: 0.21, 0.27, and 1.09 μg/ml, respectively). ITR had no activity against Fusarium spp. (n = 9; GM MIC: 32 μg/ml), but AMB was found to be the most effective antifungal against the tested members of this genus, followed by CAS and VOR (GM MICs: 0.86, 1.59, and 2.72 μg/ml, respectively). These data should be used to design future targeted clinical efficacy trials. We also report on several fungal species that are rarely encountered in the clinical laboratory, for which little information about drug sensitivities was previously available.