In vitro sensitivity to antiviral agents of herpes simplex viruses isolated from patients with herpetic keratitis

: Thirty-five clinical isolates of herpes simplex virus type 1 (HSV-1) from 34 patients (35 eyes) with herpetic keratitis were examined in vitro for 5-iodo-2'-deoxyuridine (IDU) and acyclovir (ACV) sensitivity. In addition, the effect of clinical treatment with these two drugs in herpetic keratitis was also investigated. The viral effective dose50 (ED50) was defined as the concentration that inhibited the plaque count by 50% compared to the count of the no drug controls. The viral ED50 of IDU ranged from 0.073 to 0.77 micrograms/ml (0.33 +/- 0.16; Mean +/- SD) and that of ACV from 0.0032 to 0.33 micrograms/ml (0.13 +/- 0.11). No virus with markedly diminished sensitivity to IDU and ACV was found. These results suggest that all HSV-1 strains isolated from patients have good sensitivity in vitro to antiviral agents.