Objective This study aimed to investigate characteristics of human cytomegalovirus (HCMV) glycoprotein H (gH) genotypes in urine, throat swab, and serum from children and breast milk from children's mothers.

Methods Fresh urine samples, throat swabs, or serum samples from children and breast milk samples from children's mothers were collected for HCMV DNA detection. The positive samples of HCMV DNA were further detected by fluorescent quantitative polymerase chain reaction (PCR) with gH typing.

Results Of 1,703 HCMV DNA-positive samples, the highest proportion (83.3%, 85/102) of children aged between 21 days and 3 months was detected positive in breast milk samples (p = 0.002), and the highest proportion (70.5%, 110/156) of children aged above 3 months was detected positive in throat swab samples (p = 0.002). HCMV in throat swab specimens is mainly high copy (p < 0.0001), and low-copy HCMV is prevalent in breast specimens (p < 0.0001). Among them, 1,059 samples were identified as gH1 genotype, 530 samples were gH2, and 114 samples were coinfection (gH1/2). There had the highest gH2 rates (32.3%) and lowest gH1 (61.0%) rates in urine samples (p = 0.041), whereas the highest gH1 rates (71.6%) and lowest gH2 rates (19.6%) were found in breast milk samples (p = 0.032). Concerning age groups, patients aged between 21 days and 3 months had the highest gH1 proportion (p = 0.017), while patients aged above 3 months had the highest gH1 and gH2 HCMV coinfection proportion (p = 0.002). Among 43 pairs of maternal and child samples corresponding to positive samples, gH genotype of 35 pairs of samples was consistent with a rate of 81.4%.

Conclusion gH1 is the predominant genotype of HCMV in each kind of sample in China. However, the distribution of the HCMV gH genotype is different among different samples.