A RAPID ASSAY TO SCREEN FOR DRUG-RESISTANT HERPES-SIMPLEX VIRUS

A rapid assay was developed to screen for herpes simplex virus (HSV) i solates that are resistant to acyclovir and other antiviral agents. Th e assay is a modified plaque reduction assay (PRA) in which the number of plaques seen in the absence of acyclovir was compared with that se en in the presence of a single cutoff concentration of acyclovir (2 mu g/mL). This assay utilizes a cell line that expresses beta-galactosid ase only after infection with HSV, Since histochemically stained plaqu es are easily visualized, small plaques can be easily enumerated. This allows the assay to be performed on dilutions of untitered specimens in the small wells of a 24-well plate and allows the results to be rea d only 2 days after inoculation of the virus, The assay performed well compared with a standard PRA and should be a valuable tool in identif ying drug-resistant HSV in a timely manner.