Strains Colonizing Different Intestinal Sites within an Individual Are Derived from a Single Founder Population

Vadim Dubinsky, Iris Dotan, Uri Gophna*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

1 Scopus citations

Abstract

Metagenomics has improved our understanding of commensal bacteria that colonize human intestines yet relies almost exclusively on fecal samples. Thus, spatial information about the niche range of these gut microbes and the level of specialized adaptation that they undergo has been inaccessible to fecal metagenomic studies. Here, we leveraged metagenomic data obtained through colonoscopy aspirates from three intestinal sites of healthy adults, and reconstructed metagenome-assembled genomes of several common gut bacteria to address intestinal site-specific evolution. We show that the genomes of bacterial strains at specific intestinal sites are clearly distinct yet are interrelated and are derived from a single founder strain colonizing multiple sites. We also reveal that within those intestinal sites, purifying selection is the dominant evolutionary force acting on Escherichia coli genomes within human hosts. Importantly, no site-specific adaptations at the level of accessory genes were detected, implying that these commensals are well-adapted to several host microniches and can therefore colonize multiple intestinal sites with high efficiency. Nevertheless, bacterial in situ growth rates differ markedly across different sections of the intestine. Metagenomics of aspirate samples can reveal unique strain- and intestinal tissue-specific genomic information. Such information may be critical for understanding bacterial contribution to gastrointestinal diseases, which involve only a part of the intestine, as is often the case in inflammatory bowel disease.

Original languageEnglish
JournalmBio
Volume14
Issue number1
DOIs
StatePublished - Jan 2023

Funding

FundersFunder number
Leona M. and Harry B. Helmsley Charitable Trust
European Research CouncilERC-AdG 787514

    Keywords

    • Bacteroides fragilis
    • Escherichia coli
    • Ruminococcus gnavus
    • evolution
    • gut microbiome
    • metagenomics

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