A Rare Case of Fungal Keratitis Caused by Plectosphaerella cucumerina Diagnosed With Repeated Corneal Scrapings: A Case Report

Plectosphaerella cucumerina is a filamentous fungus that infects plants and crops, but there are few previous reports of human infections. The current case was an 82-year-old woman who was referred to us for corneal infection in her left eye that did not improve with antibacterial and anti-inflammatory treatment. The best-corrected visual acuity (BCVA) of the eye at the first visit to us was hand motion. Slit-lamp examination revealed extensive white infiltration and ulceration in the anterior corneal stroma of the left eye. Intensive antibacterial and antiviral treatment for one month did not improve the condition of the cornea. Although initial culture testing and polymerase chain reaction (PCR) testing of corneal scraping samples did not reveal the causative microorganism, repeated culture testing identified P. cucumerina. The corneal infection eventually subsided after topical and systemic treatment with voriconazole (VRCZ). The final BCVA in the left eye was 1.3 logMAR. This was a rare case of fungal keratitis due to P. cucumerina. Our case suggests that it is important to perform repeated examinations with corneal scrapings, especially when the treatment response is poor.