Determination of genotype distribution and polymorphism in human cytomegalovirus (CMV) strains

The human cytomegalovirus (HCMV) has different genotypes. By determining these genotypes in different disease groups, the association between two or more infections can be found. The most frequent genetic polymorphisms found in the gB (UL55) and gH (UL75) genes, where genotyping is performed on the glycoproteins of the virus' envelope. We performed phylogenetic analyses of the DNA sequences of the gB and gH genes from 50 CMV-positive patients, using the MEGA6.0 program. In our phylogenetic analysis, the gB region in 48 patients was amplified, resulting in the following genotypes: 23 (47,9%) of these patients harboured gB1, 8 (16,6%) gB2, 11 (22,9%) gB3; and one patient gB4. Whereas in five patients (10,4%) a gB2/3 mixed genotype was found. For the amplified UL75 (gH) gene region, the patients' genotypes were 7 (14%) gH1 and 43 (86%) gH2. The gB1 and gH2 genotypes were found in higher ratios. From our sequence analysis polymorphisms were observed, where the peptide changes in the gB region are frequently found in the gp166 protein. From the clinical features, we found that the R51S, F52L, E55R, N56T and A/T57P polymorphisms are located in the gH gene regions of all of our patients. These polymorphisms have not been reported previously. Hence, our study contributes to the better understanding of the CMV genome evolution in terms of host-pathogen intercitions.