The increased detection of recombinant norovirus GII.4 Sydney_2012[P16] strains in hospitalized pediatric patients with gastroenteritis in Shanghai, China.

BACKGROUND

To understand the genetic diversity and recombination of norovirus infection in children with hospital-acquired acute gastroenteritis in Shanghai, and to provide a scientific basis for the prevention of norovirus infection in hospitalized children.

METHODS

12,485 stool specimens of children with hospital-acquired acute gastroenteritis were collected from October 2018 to June 2021. Gene amplification and sequencing of VP1, RdRp and RdRp-VP1 region were performed on norovirus-positive specimens using RT-PCR method. Genotyping and recombination analysis of sequenced sequences were performed using online analysis tools.

RESULTS

The positive rate of norovirus infection in children with hospital-acquired diarrhea by real-time quantitative RT-PCR was 16.2% (2,017/12,485). Based on the gene sequencing analysis of norovirus across the RdRp-VP1 region, nine norovirus recombinant strains were detected. From October 2018 to September 2020, the proportion of norovirus GII.4 Sydney_2012[P31] was 56.5% (231/409), while the proportion of GII.4 Sydney_2012[P16] was only 1.2% (5/409) in the same period. However, from October 2020 to June 2021, the detection rate of the recombinant strain GII.4 Sydney_2012[P16] increased to 38.8% (57/147), which exceeded that of the recombinant strain GII.4 Sydney_2012[P31] (19.0%, 28/147).

CONCLUSIONS

Norovirus GII.4 Sydney_2012 remained the main prevalent genotype, but the recombinant strain of GII.4 Sydney_2012[P16] had an increased positivity rate since October 2020. It is imperative that surveillance and management of hospital-acquired norovirus acute gastroenteritis in hospitalized children be strengthened to prevent nosocomial norovirus outbreaks.