Fusarium Keratitis—an upcoming threat in Germany?

Abstract

Background: Fungal keratitis due to Fusarium species is known to be typical of developing countries; however, with the increasing use of contact lenses a rise of Fusarium keratitis has been observed in Germany. Methods: In a monocentric retrospective study, we analyzed all patients who presented to our university eye hospital with infectious keratitis between January 2011 and December 2021 and had a proof of Fusarium species in either microscopy, culture or PCR. Results: We could identify 13 patients with a proof of Fusarium species. A significant increase of cases in 2021 was observed. In 76.9% of our cases the patients were female and in 76.9% the patients had a history of prior contact lens use. In only 4 cases the initial corneal sample gave a positive result for Fusarium. On average the suspicion of fungal keratitis arose 13.1 days after onset of symptoms, correct diagnosis was achieved after 14.6 days. All isolated specimens showed resistance against at least one of the common fungicides. In 70% of our cases treatment with penetrating keratoplasty was necessary. The patients showed a 57.1% recurrence rate after penetrating keratoplasty. In 80% of our cases best documented visual acuity after Fusarium keratitis was ≤ 0.4. Conclusion: Due to difficult detection and a high resistance rate to common antifungals, Fusarium keratitis is prone to delayed diagnosis and limited treatment outcomes. Whenever risk factors are present and infectious keratitis does not respond to antibiotics, antimycotic treatment must be initiated. Early keratoplasty may be necessary.