Malignant Keratitis Caused by a Highly-Resistant Strain of Fusarium Tonkinense from the Fusarium Solani Complex

Abstract

Fusarium spp. are moulds ubiquitously distributed in nature and only occasionally pathogenic for humans. Species of the Fusarium solani complex are the predominant keratitis-inducing pathogens, because they are endowed with proper virulence factors. These fungi can adhere to the cornea creating a biofilm and, with the help of enzymes and cytotoxins, penetrate the cornea. Whereas an intact cornea is hardly able to be invaded by Fusarium spp. in spite of appropriate virulence factors, these opportunistic fungi may profit from predisposing conditions, for example mechanical injuries. This can lead to a progressive course of corneal infection and may finally affect the whole eye up to the need for enucleation. Here, we present and discuss the clinical, microbiological and histopathological aspects of a particular case due to Fusarium tonkinense of the Fusarium solani complex with severe consequences in a patient without any obvious predisposing factors. A broad portfolio of antifungal agents was applied, both topically and systemically as well as two penetrating keratoplasties were performed. The exact determination of the etiologic agent of the fungal infection proved likewise to be very challenging.

Infectious Crystalline Keratopathy after Penetrating Keratoplasty with Light and Electron Microscopic Examination

“…The whitish branching opacities are usually localized in the anterior corneal stroma, but deep stromal involvement has also been described in single cases 9 . In contrast to classical infectious keratitis 10 , 11 , 12 , 13 , ICK has an indolent and less aggressive but therapy-resistant clinical course.…”

Indications and Results of Emergency Penetrating Keratoplasty With Simultaneous Cataract Surgery (“Triple-PKP à Chaud”)

“…11,12 Emergency PKPs, especially in cases of infectious etiology, 12,[21][22][23][24] require a sufficiently large graft diameter to remove the diseased tissue, which is not always successful. 25,26 For large diameter grafts (here: 9.0-14.0 mm), it is necessary to weigh the risks of a large diameter against a recurrence of the underlying disease, especially in infectious conditions.…”

Trans-kingdom fungal pathogens infecting both plants and humans, and the problem of azole fungicide resistance

“…A malignant keratitis case caused by a highly-resistant F. solani strain highlights the importance of proper detection, identification, and antifungal susceptibility testing (Schrecker et al, 2021 ). The causal agent was identified by morphology, ITS and TEF sequences as F. tonkinense belonging to the F. solani species complex.…”