Abstract
Persistent diarrhea of unknown etiology in children under 2 years of age is a common problem and poses a major challenge for the health sector. However, knowledge of the composition and dysbiosis of the intestinal phageome, phage-associated bacteriome in the persistent diarrhea remains limited. In this study, a process for phage enrichment and metagenomic extraction was developed and applied to recover gut phage metagenomes from 30 healthy children and 30 children with persistent diarrhea for high-throughput sequencing. Taxonomic annotation using Kraken2 revealed that, besides Norwalk virus, Primate bocaparvovirus 1 and Human-associated gemykibivirus 2, phage communities in the diarrhea group showed reduced diversity and contained sample-dependent phages targeting Salmonella enterica, Enterobacter, Shigella flexneri, Clostridioides difficile, Pseudomonas aeruginosa, Streptococcus miti, uropathogenic Escherichia coli and functioned balancing bacterial communities. Bacterial fraction in the metagenomic datasets reflected clear patterns of dysbiosis, including a severe deficiency of beneficial bacteria, an increase in Firmicutes, a marked decline in Actinobacteria, Bacteroidetes, Proteobacteria and sample-dependent enrichment of Enterococcus, Escherichia and Acinetobacter in diarrhea cases. This study, for the first time, investigated the dynamics of gut phageome, phage-associated bacteriome in children with persistent diarrhea of unknown causes in Vietnam, providing new insight for complementary treatment.