Intestinal microbiota profiles in infants with acute gastroenteritis caused by rotavirus and norovirus infection: a prospective cohort study

Objective: To compare the intestinal microbiota profiles in infants following rotavirus (RV) and human norovirus (HNoV) infection.

Methods: Faecal specimens from 18 infants {mean age 11.8 months [standard deviation (SD) 3.0] months} with acute gastroenteritis caused by RV (G9P8) and 24 infants [mean age 8.8 (SD 6.4) months] with acute gastroenteritis caused by HNoV (GII) infection were collected prospectively. The faecal microbiome was assessed by 16S rRNA amplicon pyrosequencing. Alpha diversity, beta diversity, deferentially abundant taxa and microbial functions were assessed by bioinformatic analysis.

Results: The Chao1 index for the HNoV group was significantly higher compared with the control group (P=0.0003), and was lower for the RV group compared with the HNoV group (P=0.0078). No significant difference in beta diversity was observed between the RV and HNoV groups. The RV group showed greater abundance of Actinobacteria at phylum level and Bifidobacterium spp., Streptococcus spp., Enterococcus spp. and Lactobacillus spp. at genus level. The HNoV group showed richness in Fusobacteria and Cyanobacteria at phylum level, and Enterococcus spp. and Streptococcus spp. at genus level. Bacillus was the characteristic genus in infected infants. In comparison with the control group, the viral group (P≤0.01), the RV group (P=0.002) and the HNoV group (P≤0.01) showed significant differences in potentially pathogenic bacteria.

Conclusions: Changes in microbiotic structure were observed in infants following RV and HNoV infection. The Chao 1 index of alpha diversity increased significantly in the HNoV group. Bacillus was the characteristic genus in infected infants. An increase in pathogenic bacteria, particularly Streptococcus spp. and Enterococcus spp., was detected in infected infants.