A rapid screen test for in vitro susceptibility of clinical herpes simplex virus isolates

A rapid screening test for antiviral susceptibility to acyclovir and foscarnet was evaluated in 320 herpes simplex virus (HSV) isolates from 197 patients. Of the isolates tested (16% HSV-1, 84% HSV-2), 60% were resistant in vitro to acyclovir and 5% were resistant to foscarnet using the plaque reduction assay. The rapid screening test, requiring only 3 days to yield a preliminary susceptibility result, was highly associated with the results of the plaque reduction assay for acyclovir and foscarnet (P < or = .001 for each) and with the clinical response to antiviral therapy (P < .001, P = .001, respectively).