Echoviruses belong to the genus Enterovirus in the Picornaviridae family, forming a large group of Enterovirus B (EVB)
within the Enteroviruses. Previously, Echoviruses were classified based on the coding sequence of VP1. In this study,
we performed a reliable phylogenetic classification of 277 sequences isolated from 1992 to 2019 based on the full-length
genomes of Echovirus. In this report, phylogenetic, phylogeographic, recombination, and amino acid variability landscape
analyses were performed to reveal the evolutional characteristics of Echovirus worldwide. Echoviruses were clustered into
nine major clades, e.g., G1–G9. Phylogeographic analysis showed that branches G2–G9 were linked to common strains,
while the branch G1 was only linked to G5. In contrast, strains E12, E14, and E16 clustered separately from their G3 and
G7 clades respectively, and became a separate branch. In addition, we identified a total of 93 recombination events, where
most of the events occurred within the VP1-VP4 coding regions. Analysis of amino acid variation showed high variability in
the a positions of VP2, VP1, and VP3. This study updates the phylogenetic and phylogeographic information of Echovirus
and indicates that extensive recombination and significant amino acid variation in the capsid proteins drove the emergence
of new strains.
The potential role of the gut microbiota in the pathogenesis
of feeding intolerance (FI) remains unclear. Understanding
the role of the gut microbiota could provide a new avenue for
microbiota-targeted therapeutics. This study aimed to explore
the associations between aberrant gut microbiota and FI in
very low or extremely low birth weight (VLBW/ELBW) preterm
infants. In this observational case-control study, VLBW/
ELBW infants were divided into two groups: FI group and
feeding tolerance (FT) group. 16S rRNA gene sequencing was
performed to analyze the gut microbial diversity and composition
of the infants. The differences in the gut microbiota of
the two groups were compared. In total, 165 stool samples
were obtained from 44 infants, among which, 31 developed
FI and 13 served as controls. Alpha diversity was the highest
in the meconium samples of the two groups. LEfSe analysis
revealed that the abundances of Peptostreptococcaceae, Clostridiales
and Clostridia in the FT group were significantly higher
than in the FI group. At the phylum level, the FI group was dominated
by Proteobacteria, and the FT group was dominated
by Firmicutes. The meconium samples of the FI group had
higher proportions of γ-proteobacteria and Escherichia-Shigella
and a lower proportion of Bacteroides compared with the FT
group. Kyoto Encyclopedia of Genes and Genomes (KEGG)
analysis demonstrated that aberrant gut bacteria in the FI group
were strongly associated with dysregulation of C5-Brancheddibasic-
acid-metabolism, protein kinases, and sporulation.
These findings reveal candidate microbial markers to prevent
FI. Increased relative abundances of γ-proteobacteria
and Escherichia-Shigella and decreased abundance of Bacteroides
in meconium were associated with an increased risk
of FI, while Peptostreptococcaceae, Clostridiales and Clostridia
reduced the risk of FI in VLBW/ELBW infants.