Eye Infections Caused by Filamentous Fungi: Spectrum and Antifungal Susceptibility of the Prevailing Agents in Germany.

Johanna Theuersbacher,Grit Walther,Mathias Roth,Oliver Kurzai,Daniel Kampik,Marie Von Lilienfeld-Toal,Kerstin Kaerger,Gerd Geerling,Anna Zimmermann

doi:10.3390/jof7070511

Abstract

Fungal eye infections can lead to loss of vision and blindness. The disease is most prevalent in the tropics, although case numbers in moderate climates are increasing as well. This study aimed to determine the dominating filamentous fungi causing eye infections in Germany and their antifungal susceptibility profiles in order to improve treatment, including cases with unidentified pathogenic fungi. As such, we studied all filamentous fungi isolated from the eye or associated materials that were sent to the NRZMyk between 2014 and 2020. All strains were molecularly identified and antifungal susceptibility testing according to the EUCAST protocol was performed for common species. In total, 242 strains of 66 species were received. Fusarium was the dominating genus, followed by Aspergillus, Purpureocillium, Alternaria, and Scedosporium. The most prevalent species in eye samples were Fusarium petroliphilum, F. keratoplasticum, and F. solani of the Fusarium solani species complex. The spectrum of species comprises less susceptible taxa for amphotericin B, natamycin, and azoles, including voriconazole. Natamycin is effective for most species but not for Aspergillus flavus or Purpureocillium spp. Some strains of F. solani show MICs higher than 16 mg/L. Our data underline the importance of species identification for correct treatment.

Highlights

Eye infections caused by fungi are serious diseases that can lead to loss of vision and blindness
Data from the German Fungal Keratitis Registry have shown that roughly one-third of cases in Germany are caused by Candida species, one-third is Fusarium keratitis, and one-third is caused by other filamentous fungi, including Aspergillus spp. [14]
To assess the epidemiological situation of keratitis caused by filamentous fungi in Germany and provide representative data on the in vitro antifungal susceptibility of the causative agents, this study aims to answer the following questions: (1) Which filamentous fungal species are causing keratitis in Germany? (2) What are the antifungal susceptibility profiles of these species? (3) Is natamycin effective against all fungal taxa causing eye infections? (4) Are there differences in the minimum inhibitory concentrations (MICs) of natamycin among Fusarium species?

Summary

Introduction

Eye infections caused by fungi are serious diseases that can lead to loss of vision and blindness. Numerous fungal species are known to cause keratitis. Wearing of soft contact lenses and ocular trauma is mostly associated with keratitis caused by filamentous fungi, whereas keratitis caused by Candida spp. most frequently occurs in patients with chronic eye disease, topical steroid use, or surgical intervention. The spectrum of filamentous fungi causing keratitis differs depending on the climate and geographic region, but Aspergillus and Fusarium species are the predominant causative agents worldwide [11,12,13]. Data from the German Fungal Keratitis Registry have shown that roughly one-third of cases in Germany are caused by Candida species, one-third is Fusarium keratitis, and one-third is caused by other filamentous fungi, including Aspergillus spp. Data from the German Fungal Keratitis Registry have shown that roughly one-third of cases in Germany are caused by Candida species, one-third is Fusarium keratitis, and one-third is caused by other filamentous fungi, including Aspergillus spp. [14]

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