The Nucleic Acid Positive Rate And Genotype Distribution Of HCMV In A Human Milk Bank In China

Objective:Preliminary studies at the molecular level of the prevalence of HCMV virus in breast milk in mainland China,as well as the genetic characteristics and molecular evolutionary laws of endemic strains,provide the basis for the safety of breast milk in China,the surveillance of HCMV epidemics,the diagnosis and prevention of related diseases,and the basis for vaccine research data.Method:Real-time RT-PCR was used to determine nucleic acid positive rate of HCMV nucleic acid from breast milk samples in Beijing,Chongqing and Inner Mongolia from 2017 to 2018,and the target gene gB glycoprotein was amplified and sequenced by Nest-PCR.MEGA and BioEdit software were used to construct the relationship tree,genotype distribution and gene characteristics analysis.Results:1 A total of 510 breast milk samples were obtained from three regions.RT-PCR detected 46.4%of donated breast milk samples and 59.2%of milk samples obtained from the mothers of premature infants were positive for HCMV DNA.Beijing,Chongqing and Inner Mongolia donated breast milk samples were 75%,57.5%and 29.%,respectively.The positive rates of HCMV DNA in milk samples obtained from the mothers of premature infants were 54.2%,69.6%,and 67.2%,respectively.The CT value of most breast milk samples were between 31-36 and the concentration of HCMV DNA was approximately 103-104 copies/ml in the HCMV DNA positive human milk samples.2 Based on the glycoprotein B(gB)gene 299-305bp,three HCMV genotypes were identified in human milk samples,which were 67.3%gB1,6.8%gB2,23.9%gB3,2%gB1 and gB3 mixed genotypes.The genotype distribution of HCMV in the three regions was not significantly different,all of which were mainly gB1 genotypes.Three genotypes of HCMV in Beijing and Inner Mongolia were detected,but gB2 was not detected in Chongqing.3 There were also three genotypes in donated breast milk samples and milk samples obtained from the mothers of premature infants.79.4%gB1,4.4.%gB2,and 16.3%gB3 were in donated breast milk samples,and 61.3%gB1,8.0%gB2,27.7%gB3,2.8%gB1 and gB3 mixed genotypes in milk samples obtained from the mothers of premature infants.The major genotypes of donated breast milk samples and milk samples obtained from the mothers of premature infants were gB1 genotypes However,mixed infections of gB1 and gB3 genotypes were found in only 4 milk samples obtained from the mothers of premature infants.4 Analysis of nucleotide and amino acid sequence homology of HCMV in 205 milks showed that the nucleotide and amino acid homology between HCMV gB target gene sequences is 76.8%-100%and 55.6%-100%,respectively.The nucleotide homology between gB1,gB2 and gB3 target gene sequences is 94.0%-100%,98.6%-100%and 92.7%-100%,respectively.The amino acid homology between gB1,gB2 and gB3 target gene sequences is 91.7%-100%,97%-100%and 83.5%-100%,respectively.57 sequences with large differences in amino acids and nucleotides were selected for analysis of nucleotide and amino acid variation.The 45-47 gB1 bases are CTA,gB2 and gB3 bases are deleted at these three positions,the 69-71 gB1 and gB2 bases are GAT and AGT,and gB3 is base-deficient at these three sites.5 Phylogenetic tree analysis of genetic genes found no significant difference in the chronological distribution of the three HCMV genotypes in breast milk,and there was no significant difference in the position of the phylogenetic tree between donated breast milk samples and samples obtained from the mothers of premature infants Phylogenetic tree analysis of genetic genes found that gB1 genotypes in milk were significantly different.The gB1 genotype was divided into three lineages based on the global sequences.Lineagesl includes sequences from Germany,Britain,Israel,Australia,USA,Greece,Belgium and China.The 2 and 3 lineages are mainly from HCMV sequences in China,Egypt and the United States.Genotypes gB2 and gB3 exist in China,Germany,Czech Republic,Italy,South Korea,the United States,France,and the Netherlands.Conclusions:This study is the first to identify HCMV infection in breast milk in Beijing,Inner Mongolia,and Chongqing,China.A preliminary analysis of the HCMV nucleic acid positive rate in donated milk samples from breast milk banks in China was slightly lower than that of mothers of preterm infants.Low,and identified the genetic characteristics,genetic polymorphisms and dynamic mutations of HCMV virus strains in the three epidemic areas,further accumulating and enriching China's HCMV virology surveillance database,providing important guarantees for the safety of breast milk banks in China.Control and vaccine research and development provide important scientific and technological support.Figure 16 table 17 reference 124.