ANTIVIRAL SUSCEPTIBILITIES AND ANALYSIS OF UL97 AND DNA-POLYMERASE SEQUENCES OF CLINICAL CYTOMEGALOVIRUS ISOLATES FROM IMMUNOCOMPROMISED PATIENTS

Antiviral susceptibilities to ganciclovir, foscarnet, and cidofovir an d sequencing of UL97 and DNA polymerase were done on 23 cytomegaloviru s (CMV) isolates from 10 immunocompromised persons with end-organ CMV disease who were treated with ganciclovir alone or ganciclovir followe d by foscarnet, Screening of UL97 for ganciclovir resistance mutations was done by restriction digest analysis. Of 14 isolates resistant to ganciclovir, 11 (79%) contained one or more UL97 mutations at codons k nown to confer resistance to this compound, and 10 (91%) had a concord ant mutant pattern by restriction digest analysis, Of 9 isolates conta ining mutations in conserved regions of the DNA polymerase, 8 were res istant to ganciclovir, and 4 were cross-resistant to cidofovir, All is olates were susceptible to foscarnet, It is concluded that ganciclovir -resistant clinical CMV isolates may contain UL97 mutations, DNA polym erase mutations, or mutations in both genes, Ganciclovir therapy map s elect for CMV isolates that are cross-resistant to cidofovir.