Prevalence of herpes simplex virus type 1 glycoprotein G (gG) and gl genotypes in patients with herpetic keratitis

Aim: Recent phylogenetic analyses on the herpes simplex virus type 1 (HSV-1) genes US4, encoding glycoprotein G (gG) and US7, encoding gl, of clinical HSV-1 isolates have led to the classification of HSV-1 into three genotypes, arbitrarily designated as A, B and C. The prevalence of the HSV-1 gG and gl genotypes and their potential disease association was determined in a large cohort of patients with herpetic keratitis (HK). Methods: Primary corneal HSV-1 isolates of 178 HK patients were genotyped by a PCR-based restriction fragment length polymorphism method targeting the viral genes US4 and US7. Results: Genotype B was more frequently expressed by the corneal HSV-1 isolates compared with genotypes A and C. Fifty-five of 178 corneal isolates (31%) had different genotypes in both loci. No clinically relevant associations were observed between the HSV-1 genotypes and disease outcome in the HK patients studied. Conclusions: The data presented demonstrate a high frequency of recombinant corneal HSV-1 isolates and suggest that clinical outcome of HSV-1-induced keratitis is independent of a gG or gl genotype.