Genetic characteristics of norovirus in children with acute gastroenteritis in a single center in Shanghai / 中华微生物学和免疫学杂志

ABSTRACT

Objective:To investigate the genetic characteristics of norovirus (NoV) in children with acute gastroenteritis in Shanghai.Methods:A total of 709 stool specimens were collected from outpatients with acute gastroenteritis in Children′s Hospital of Shanghai from October 2018 to September 2019. Real-time RT-PCR was used for qualitative detection of NoV, and RT-PCR was used to identify the genotypes of NoV with the primers of VP1 gene, RdRp region and RdRp-VP1 region. SPSS20.0 statistical software was used for data processing and bioinformatics software was used for homology, phylogenetic and recombination analysis of NoV gene sequences.Results:NoV was detected in 265 out of the 709 stool specimens with a positive rate of 37.4%. Sequence analysis of RdRp region and VP1 gene showed that seven different genotypes including GⅡ.P16-GⅡ.2, GⅡ.P12-GⅡ.3, GⅡ.Pe-GⅡ.4_Sydney 2012, GⅡ.P7-GⅡ.6, GⅡ.P8-GⅡ.8, GⅡ.P21-GⅡ.13 and GⅡ.P17-GⅡ.17 were detected from 111 NoV-positive specimens. The predominated genotype was GⅡ.P16-GⅡ.2 (30.6%, 34/111), followed by GⅡ.Pe-GⅡ.4_Sydney 2012 (27.0%, 30/111) and GⅡ.P12-GⅡ.3 (24.3%, 27/111). Two new NoV recombinant strains belonging to GⅡ.P21-GⅡ.13 genotype were identified and the recombination site was in the junction region of ORF1 and ORF2. NoV infection occurred every month, but the predominant genotype was different. No significant difference in the positive rates of NoV was found between male and female patients ( P=0.329). However, there were significant differences between different age groups ( P=0.011) and the children in the age groups of >11-12 years old and >2-3 years old had higher rates of NoV infection. Conclusions:The predominated recombinant NoV strains belonged to GⅡ.P16-GⅡ.2, GⅡ.Pe-GⅡ.4_Sydney 2012 and GⅡ.P12-GⅡ.3 genotypes, and two new recombinant NoV strains (GⅡ.P21-GⅡ.13) were found in Shanghai during October 2018 to September 2019. Gene sequencing across ORF1 and ORF2 was conducive to better understanding the NoV genotypes and recombination.