Imported pythium insidiosum keratitis after a swim in Thailand by a contact lens-wearing traveler

Abstract

A 30-year-old woman with a history of contact lens wear and exposure to swimming pool water in Thailand presented with a non-responsive, progressive corneal ulcer of the right eye. Confocal microscopy evidenced septate linear branching structures, raising suspicion of fungal keratitis. She was promptly treated with topical antibiotics and both topical and intravenous caspofungin plus voriconazole. Worsening of the clinical picture after 1 month of intensive medical therapy led to a large therapeutic penetrating keratoplasty being performed. Corneal cultures grew a mold-like organism, which was identified by sequencing as Pythium insidiosum, an aquatic oomycete. After 4 years of follow-up, the graft exhibits no infection relapse, but graft transparency has been lost after two rejection episodes. Keratoplasty combined with antifungal treatment may offer a cure to P. insidiosum keratitis, although long-term preservation of corneal transparency is difficult to obtain.

Figure 1.

(A) Slit-lamp photograph and (B) fluorescein eye stain on admission showing a large central corneal ulcer with underlying dense stromal infiltrates. (C) Image magnification shows a reticular pattern of subepithelial and superficial stromal infiltration. (D) Confocal microscopy reveals highly reflective branching structures resembling fungal hyphae. (E) Worsening of clinical features at day 31. (F) Clinical photograph 6 months after the penetrating keratoplasty.

Figure 2.

Histopathology of the excised host cornea. (A–C) Gomori methenamine silver revealing branching hyphae (arrows in C) within the anterior part of the corneal stroma.