Gut dsDNA virome shows diversity and richness alterations associated with childhood obesity and metabolic syndrome

Changes in the human gut microbiome are associated with obesity and metabolic syndrome, but the role of the gut virome in both diseases remains largely unknown. We characterized the gut dsDNA virome of 28 school-aged children with healthy normal-weight (NW, n = 10), obesity (O, n = 10), and obesity with metabolic syndrome (OMS, n = 8), using metagenomic sequencing of virus-like particles (VLPs) from fecal samples. The virome classification confirmed the bacteriophages' dominance, mainly composed of Caudovirales. Notably, phage richness and diversity of individuals with O and OMS tended to increase, while the VLP abundance remained the same among all groups. Of the 4,611 phage contigs composing the phageome, 48 contigs were highly prevalent in ≥80% of individuals, suggesting high inter-individual phage diversity. The abundance of several contigs correlated with gut bacterial taxa; and with anthropometric and biochemical parameters altered in O and OMS. To our knowledge, this gut phageome represents one of the largest datasets and suggests disease-specific phage alterations.

Whole-genome of Mexican-crAssphage isolated from the human gut microbiome

Objectives

crAssphage is a newly found phage described as the most abundant virus in the human gut microbiome. The majority of the crAssphage proteins are unknown in sequences databases, and its pathogenicity and epidemiology in humans are yet unclear. Hence, being one of the most abundant phages in the human gut microbiome more investigation at the genomic level is necessary to improve our understanding, especially in the Latin American population.

Data description

In this article, we provide the whole genome of a crAssphage isolated from the human gut microbiome of the Mexican population, which was named Mexican-crAssphage. The genome consists of 96,283 bp, G+C content of 29.24% and 87 coding sequences. Notably, we did not find any transfer RNA genes in the genome sequence. We also sequenced viral-like enriched particles from 28 fecal samples, and we detected the presence of the Mexican-crAssphage genome in 8 samples (28.5%). To our knowledge, our data is the first whole genome report of the crAssphage isolated from the Latin American Population and provides valuable information for the experimental characterization of the most abundant human gut bacteriophage. The whole genome shotgun project of the Mexican-crAssphage is available at DDBJ/ENA/GenBank under the GenBank MK069403.

Composition of gut microbiota in obese and normal-weight Mexican school-age children and its association with metabolic traits

BACKGROUND

Childhood obesity is a serious public health problem in Mexico. Adult gut microbiota composition has been linked to obesity, but few studies have addressed the role of gut microbiota in childhood obesity.

OBJECTIVES

The aim of this study is to compare gut microbiota composition in obese and normal-weight children and to associate gut microbiota profiles with amino acid serum levels and obesity-related metabolic traits.

METHODS

Microbial taxa relative abundance was determined by 16S rRNA sequencing in 67 normal-weight and 71 obese children aged 6-12 years. Serum amino acid levels were measured by mass spectrometry. Associations between microbiota composition, metabolic parameters and amino acid serum levels were tested.

RESULTS

No significant differences in phyla abundances or Firmicutes/Bacteroidetes ratios were observed between normal-weight and obese children. However, Bacteroides eggerthii abundance was significantly higher in obese children and correlated positively with body fat percentage and negatively with insoluble fibre intake. Additionally, Bacteroides plebeius and unclassified Christensenellaceae abundances were significantly higher in normal-weight children. Abundance of both these species correlated negatively with phenylalanine serum levels, a metabolite also found to be associated with obesity in Mexican children.

CONCLUSIONS

The study identified bacterial species associated with obesity, metabolic complications and amino acid serum levels in Mexican children.