GANCICLOVIR SUSCEPTIBILITIES AND ANALYSIS OF UL97 REGION IN CYTOMEGALOVIRUS (CMV) ISOLATES FROM BONE-MARROW RECIPIENTS WITH CMV DISEASE AFTER ANTIVIRAL PROPHYLAXIS

Ganciclovir susceptibilities and UL97 sequences were analyzed in 20 cy tomegalovirus (CMV) isolates recovered from 15 bone marrow transplant recipients with active CMV infection after prophylaxis with acyclovir (group I; 12 isolates) or after acyclovir prophylaxis followed by ganc iclovir therapy (group II; 8 isolates). All group I isolates were susc eptible to ganciclovir. Five group II isolates were susceptible to gan ciclovir, and 3 isolates tall from the same person) were resistant to ganciclovir (IC50 > 12 mu M. Ganciclovir resistance UL97 mutations wer e found in 4 group II isolates, including a ganciclovir-susceptible is olate obtained from 1 patient after 41 days of therapy with ganciclovi r and 3 ganciclovir-resistant isolates obtained from another patient a fter 73, 116, and 132 days of treatment with ganciclovir. Ganciclovir- resistant CMV isolates may emerge rapidly in bone marrow transplant re cipients who are treated with ganciclovir after receiving prophylaxis with acyclovir.