Cytomegalovirus retinitis and viral resistance. Prevalence of resistance at diagnosis, 1994. Cytomegalovirus Retinitis and Viral Resistance Study Group
D. A. Jabs, J. P. Dunn, C. Enger, M. Forman, N. Bressler and P. Charache
Department of Ophthalmology, Johns Hopkins University School of Medicine, Baltimore, Md., USA.
OBJECTIVE: To determine the prevalence of cytomegalovirus (CMV) isolates
resistant to ganciclovir sodium or foscarnet sodium at the time of
diagnosis of CMV retinitis, prior to the initiation of therapy. DESIGN:
Prospective epidemiologic study. SETTING: An acquired immunodeficiency
syndrome ophthalmology clinic. PATIENTS: Patients with acquired
immunodeficiency syndrome and newly diagnosed CMV retinitis. INTERVENTION:
Culturing blood and urine samples for CMV and testing of all positive
isolates for sensitivity to ganciclovir and foscarnet. MAIN OUTCOME
MEASURE: Prevalence of the following: blood culture isolates resistant to
ganciclovir (inhibitory concentration 50% [IC50] > 5.5 mumol/L) or
foscarnet (IC50 > 400 mumol/L) and urine culture isolates resistant to
ganciclovir or foscarnet. RESULTS: Forty-nine patients were enrolled during
a 13-month period. Forty-four patients had blood culture samples that could
be evaluated; of these, 66% were positive (59% of patients). Thirty-four
patients had urine cultures that were evaluable; of these, 82% were
positive (57% of patients). Overall, 78% of patients had either a urine or
blood culture sample positive for CMV. No blood culture isolates were
resistant to ganciclovir, and only 1 urine culture isolate (2% of patients)
was resistant to ganciclovir. Three percent of blood culture isolates and
4% of urine culture isolates (2% and 2% of patients, respectively) were
resistant to foscarnet. Overall, 4% of patients had either a blood or urine
culture isolate resistant to foscarnet. CONCLUSION: Resistance to
ganciclovir or foscarnet at the time of diagnosis of CMV retinitis is
uncommon.
