1746. Prevalence and Resistance Patterns of Cytomegalovirus Viremia in Immunocompromised Patients

BACKGROUND: We noted a recent increase in the number of patients with CMV viremia among immunocompromised children at our institution. The study was undertaken to determine the prevalence of CMV viremia and to evaluate factors associated with the development of antiviral drug resistance. METHODS: A retrospective study of immunocompromised hosts 0–21 years of age who had CMV viremia (2007–2017). We collected demographic data as well as details of antiviral therapy and resistance testing. RESULTS: A total of 31 patients were identified including 10 (32%) during the last 2 years. The age range was 3 months to 20 years (median 12.6 years); 23 (74%) were male and 12 (39%) were African American. Among the 31 patients, 18 had hematopoietic stem cell transplantation, 5 had primary immunodeficiency (2 common variable immunodeficiency, 1 SCID, 1 Langerhans cell histiocytosis, 1 DiGeorge syndrome), 4 had malignancies receiving chemotherapy, 3 with heart transplantation and one 17 year old with newly diagnosed HIV infection who presented with CMV pneumonia and viremia. Antiviral resistance testing was performed on 7 CMV isolates: 5 due to persistent viremia (> 1 months) despite treatment, and 2 prior to starting antiviral therapy. CMV resistance was identified in 3 patients including 2 with CVID and one with Hodgkin’s disease status post bone marrow transplantation. The 2 CVID patients had other comorbidities including chronic diarrhea and malabsorption and were TPN dependent. Both were diagnosed with CMV colitis and one also had pneumonitis. One had received a prolonged oral valganciclovir course (> 1 year) prior to diagnosis of resistance and the other received long-term intermittent oral valganciclovir courses. The patient with Hodgkin’s disease received a prolonged IV ganciclovir course. All 3 tested positive for UL97 mutation and one had both UL97/UL54 gene mutations. CONCLUSION: Most of our patients with CMV viremia were transplant patients. Antiviral drug resistance was detected among 3 of 31 (10%) of our patients during the study period. Two had malabsorption that may have resulted in sub-therapeutic blood levels. Treatment with oral valganciclovir should be avoided in patients with poor gut absorption because it may increase risk of drug resistance. DISCLOSURES: All authors: No reported disclosures.