Cytomegalovirus (CMV) Culture Results, Drug Resistance, and Clinical Outcome in Patients with AIDS and CMV Retinitis Treated with Foscarnet or Ganciclovir

The objectives of the study were to examine the clinical significance of cytomegalovirus (CMV) culture results and drug susceptibilities in CMV isolates from patients with AIDS-related CMV retinitis. Blood and urine for CMV culture were obtained from 207 patients with newly diagnosed CMV retinitis who were enrolled in a randomized trial comparing foscarnet and ganciclovir. Culture-positive rates at baseline were 45% and 71% for blood and urine, respectively. Rates decreased 3- to 10-fold after initiation of either treatment. Mortality was related to both positive baseline blood and urine cultures; adjusted relative risks were 1.97 and 2.03, respectively. Positive blood cultures at baseline were associated with more rapid retinitis progression. Drug-resistant CMV was found, over comparable follow-up periods on assigned treatment, in 4 of 8 ganciclovir-assigned patients with persistent viremia and 0 of 5 foscarnet-assigned patients with persistent viremia. Results of virologic assays of blood appear to be associated with clinical outcome of CMV retinitis.