Acyclovir resistance/susceptibility in herpes simplex virus type 2 sequential isolates from an AIDS patient.

The biological characterization of a number of sequential herpes simplex virus type 2 (HSV-2) isolates obtained from an AIDS patient undergoing sequential courses of antiviral treatment due to an extended mucocutaneous genital lesion is reported. Resistance to acyclovir (ACV) and related compounds was linked to a thymidine kinase-deficient (TK-) phenotype. After ACV discontinuation and a course of treatment with foscarnet, a new isolate was recovered, characterized by loss of the ACV-resistant trait and production of a functional TK enzyme. Data presented stress the need for monitoring chemosensitivity of HSV isolates in AIDS patients while suggesting that for better control of the infection, these patients should benefit from alternative treatments with drugs aimed at different viral targets.