Ganciclovir-resistant cytomegalovirus encephalitis in a hematopoietic stem cell transplant recipient.

We describe a 41-year-old patient, who upon receiving a bone marrow transplant in order to treat chronic myeloid leukemia, developed cytomegalovirus (CNV) retinitis and encephalitis under the ganciclovir maintenance treatment. Analysis of sequential viral isolates recovered from the patient's cerebrospinal fluid and blood showed CMV DNA with a UL97 mutation (M460V) known to confer ganciclovir resistance. Foscarnet resistance mutations were not found. Although therapy was switched to foscarnet when ganciclovir resistance was suspected, the patient was lost on posttransplant day 200.