HCMV studies were performed using cell-associated low-passage clinical isolates CH1914 and BI-615. CH19 is resistant to the first-line HCMV antiviral drug, ganciclovir (GCV), while BI-6 is susceptible to GCV. Additional experiments were performed using CMVPT30-GFP16, which expresses green fluorescent protein and produces extracellular virus.