Acyclovir-resistant herpetic keratitis in a solid-organ transplant recipient on systemic immunosuppression

Abstract

Liam Daniel Turner,1 Peter Beckingsale1,2,31Princess Alexandra Hospital; 2Terrace Eye Centre; 3Laser Sight, Brisbane, Queensland, AustraliaPurpose: To report a case of acyclovir-resistant herpetic keratitis in a solid-organ lung transplant recipient that was effectively treated with topical trifluridine.Methods: A case of a 35-year-old female with herpetic epithelial keratitis resistant to acyclovir is described. The patient presented following treatment for 4 weeks with topical acyclovir ointment five times per day and oral valacyclovir 1 g three times per day for herpetic keratitis with no resolution of the epithelial defect or symptoms. Corneal scrapes and swabs were taken for confirmation of the diagnosis and resistance testing. The results were positive for herpes simplex virus 1 and showed acyclovir resistance (inhibitor concentration 90 = 200 µg/mL) and foscarnet sensitivity (inhibitor concentration 90 = 200 µg/mL). The patient was treated with topical trifluridine 2-hourly for 3 weeks and weaned off the drops over the following week.Results: The patient showed resolution of the epithelial defect, but did have significant corneal toxicity associated with the use of the trifluridine. At 8 weeks, the patient had some stromal shadowing associated with the recent active infection, but symptoms had settled.Conclusion: This case documents the effective use of topical trifluridine in proven acyclovir-resistant herpetic keratitis. It highlights three things: (1) the importance of considering topical trifluridine as an alternative to topical acyclovir in unresponsive disease; (2) the need to consider solid-organ transplant recipients in the immunocompromised population with resistant herpetic disease, and (3) the need to look for alternatives to treatment of resistant herpetic disease.Keywords: acyclovir resistance, herpetic keratitis, trifluridine