assessment of the human cytomegalovirus ul97 gene for identification of resistance to ganciclovir in iranian immunosuppressed patients

background: human cytomegalovirus (hcmv) infections are a major cause of morbidity and mortality among immunocompromised patients. prolonged antiviral therapy is a cause of mutation and drug resistance in the hcmv genome. objectives: the aim of this study was to identify resistance to ganciclovir (gcv) in iranian immunosuppressed patients at two different stages of the disease: early (before gcv is initiated) and late (after six months of gcv therapy). patients and methods: in this study, 87 specimens from iranian patients were amplified using nested pcr amplification of the ul97 gene. sequence analyses of products were performed for identifying the mutated codons. results: the present study show that the most frequent gcv-resistant mutations occurred in codons a594v (26.43%), h520q (18.39%), and m460v (13.79%), consequently occurring at a low frequency in the l595s (2.29%), e596g (1.14%), and del 594 (1.14%) codons, and with intermediate frequency in the c592g (10.34%), m460i (9.19%), and c603w (6.89%) codons. we describe for the first time a new gcv-resistance mutation, the deletion of codon 594, in the ul97 gene of iranian hcmv patients after gcv therapy, following renal transplantation. conclusions: the findings of the present study can be utilized to detect gcv resistance patterns among iranian immunocompromised patients and to treat hcmv infections accordingly.