Ganciclovir sensitivity of cytomegalovirus at diagnosis and during treatment of cytomegalovirus pneumonia in marrow transplant recipients.

Cytomegalovirus (CMV) often persists in the lungs of marrow transplant patients with CMV pneumonia, despite ganciclovir (GCV) treatment. To determine whether GCV resistance contributes to viral persistence, the susceptibilities of CMV isolates from diagnostic bronchoalveolar lavage samples and CMV isolates obtained during treatment or from autopsy lung tissue from 12 patients were compared by DNA hybridization. Resistance (50% effective dose, > 12 microM) was detected in an isolate from only one patient who had also received several courses of GCV. GCV resistance did not explain the persistence of CMV in the lung.