A deletion at CMV UL54 codon 524 without co-existing resistance-associated mutation at UL97 confers resistance to ganciclovir: A case report.

Sequencing of Cytomegalovirus (CMV) genes to investigate antiviral resistance is a growing area of interest as treatment for CMV infection becomes more widely available and used. Using conventional sequencing methods, we identified a deletion in UL54 gene, del524, which conferred resistance to ganciclovir in a renal transplant recipient, in the absence of a co-existing resistance-conferring mutation in UL97 gene. This case report reinforces that both UL97 and UL54 genes should be sequenced when exploring CMV antiviral resistance as mutations have been identified in both genes independently of each other.