The prevalence and molecular characteristics of isolates from 173 immunocompetent patients with herpetic keratitis (HK) whowere infected with acyclovir (ACV)-resistant(ACVR) corneal herpes simplex virus (HSV)-1 was determined. Isolates from 11 (6.4%) of the patients were ACVR, and 9 of these 11 patients were refractory to therapy with ACV; the ACVRisolates from 5 and 1 of these 9 patients were cross-resistant to gancyclovir and to both gancyclovir and foscarnet, respectively. Of the 11 ACVRisolates, 10 had, in the thymidine kinase gene, mutations that presumably conferred the ACVRphenotype. These data demonstrate a relatively high prevalence of corneal HSV-1 ACVRisolates in patients with HK, which emphasizes the need to monitor for ACV susceptibility in patients with HK who are refractory to therapy with ACV.,
The Journal of Infectious Diseases
Erasmus MC: University Medical Center Rotterdam

Duan, R, de Vries, R.D, Osterhaus, A.D.M.E, Remeijer, L, & Verjans, G.M.G.M. (2008). Acyclovir-resistant corneal HSV-1 isolates from patients with herpetic keratitis. The Journal of Infectious Diseases, 198(5), 659–663. doi:10.1086/590668