Fungal Keratitis Caused by Talaromyces coalescens: A Case Report

Fungal keratitis is a severe corneal infection, and the causative fungi include various rare fungal species. Fungal keratitis caused by Talaromyces species has yet to be reported, and there is no information about this fungus as a cause of keratitis. A 77-year-old man developed fungal keratitis while waiting for a donor cornea due to bullous keratopathy in his left eye. Fungal culture of a corneal scraping grew filamentous fungi, which were morphologically identified as Paecilomyces species. The corneal infection did not improve after topical administration of 1% voriconazole, and ribosomal DNA sequencing definitively verified the fungus to be Talaromyces coalescens. The lesion gradually improved after switching to topical 5% natamycin. Antifungal susceptibility tests determined the high minimum inhibitory concentrations of voriconazole to be > 8 μg/mL. This is the first report of Talaromyces fungal keratitis. Clinicians, especially those in ophthalmology, need to be aware of this rare fungus.