Aspergillus flavus Keratitis After Penetrating Keratoplasty

Fungal keratitis is a rare but severe complication following penetrating keratoplasty (PKP). We report the clinical course, rapid deterioration, and management of a case of Aspergillus flavus keratitis occurring three months after PKP. A 69-year-old woman with Fuchs' endothelial dystrophy developed pseudophakic bullous keratopathy following cataract surgery. She underwent an uneventful PKP. At two months postoperatively, the graft remained clear with a visual acuity of 2/10. Three months after keratoplasty, the patient presented with pain, redness, mucopurulent discharge, and decreased vision. Slit-lamp examination revealed graft haze with a central epithelial defect, stromal infiltrates, and striae that rapidly progressed into the adjacent recipient cornea. Corneal scrapings were obtained for direct microscopic examination and culture, which revealed septate fungal filaments identified as Aspergillus flavus. Both the donor corneoscleral rim and the recipient corneal tissue were cultured at the time of surgery, and all cultures returned negative for fungal growth. Considering the negative donor cultures, the delayed onset of infection, and the presence of a persistent epithelial defect, the infection was most consistent with a postoperative superinfection rather than a donor-transmitted source. Intensive topical voriconazole and amphotericin B, along with systemic voriconazole, were initiated. Antifungal susceptibility testing was not performed due to the urgent need to initiate empirical therapy following the identification of fungal filaments on direct microscopy and rapid clinical deterioration. Despite aggressive antifungal therapy, the infection progressed, leading to graft melting and corneal perforation. The patient underwent therapeutic PKP, open sky vitrectomy, and removal of the posterior chamber intraocular lens (PC-IOL). Following the removal of the PC-IOL intraoperatively, the patient remained aphakic. Postoperatively, there was no recurrence of infection, and best-corrected visual acuity (BCVA) stabilized at 6/10 with aphakic spectacle correction. This case highlights the virulence of Aspergillus flavus and the challenges in managing post-keratoplasty fungal keratitis, especially when predisposing factors such as persistent epithelial defect and corticosteroid use are present. Early diagnosis and prompt medical and surgical intervention are critical to preserving ocular integrity.