A complex defined human gut microbiome assembled from hCom1 and iteratively augmented after fecal challenge to improve stability and colonization resistance in gnotobiotic mice.
Taxonomy
| Taxon | Ontology ID | Functional Roles | Abundance |
|---|---|---|---|
| defined human gut bacterial members — ontology label: Bacteria | NCBITaxon:2 · TaxonMech · TraitMech |
CROSS_FEEDER
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N/A |
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Ecological Interactions
The graph shows only explicitly linked interaction participants. Community members without an asserted participant link are omitted; membership alone does not imply an interaction.
Fecal-Challenge-Guided Community Augmentation
Species identified after challenging hCom1-colonized mice with fecal communities informed the assembly of hCom2. The intervention changes community membership; filling open niches is its ecological interpretation, not a directly measured complete metabolic or spatial niche map.
Biological Processes:
- multi-organism process (GO:0044419 · PathwayMech)
Membership augmentation produced a community with greater fecal-challenge resilience in the tested mice. PARTIAL mechanism: niche occupancy is a proposed explanation rather than a selectively measured mediator, and unrelated donors expose residual invasibility.
HYPOTHESIZED mediation: broader niche occupancy could contribute to hCom2 resistance, but observing resistance in hCom2 does not establish that the augmentation step or any added species is necessary. The study does not resolve the protective strains or molecular pathway.
Evidence
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PMID:36070752 - SUPPORT (IN_VIVO)"We identified new species that engrafted following fecal challenge and added them to hCom1, yielding hCom2."
hCom2 Fecal-Challenge Stability
In gnotobiotic mice, hCom2 was more resilient than hCom1 to fecal challenge. The primary study also reports weaker resilience to unrelated fecal donors. Stability is therefore donor- and experiment-dependent, not complete exclusion or universal human-microbiome equivalence.
Biological Processes:
- multi-organism process (GO:0044419 · PathwayMech)
Evidence
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PMID:36070752 - SUPPORT (IN_VIVO)"hCom2 exhibited increased stability to fecal challenge"
hCom2 Escherichia coli Colonization Resistance
hCom2 conferred robust resistance to the tested pathogenic E. coli challenge in gnotobiotic mice. The phenotype is community-level resistance, not facilitation of the invader and not proof that each bacterial member is protective. The responsible strains and molecular mechanism remain unresolved.
Biological Processes:
- defense response to bacterium (GO:0042742 · PathwayMech)
Evidence
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PMID:36070752 - SUPPORT (IN_VIVO)"robust colonization resistance against pathogenic Escherichia coli"
Knowledge gaps & discussions (1)
KNOWLEDGE_GAP OPEN Which membership changes and ecological mechanisms cause the challenge phenotypes?
Preserve the augmented-community and pathogenic-challenge outcomes without assigning colonization-facilitation labels. Phylum-dropout results narrow candidate explanations but do not identify a necessary individual strain or distinguish direct protection from altered community architecture. Unrelated-donor invasion limits universal stability. Existing non-graph re-evidencing debt remains under issue 765; no restricted article body is reintroduced into the repository.
Attaches to: ecological_interactions#Fecal-Challenge-Guided Community Augmentation, ecological_interactions#hCom2 Fecal-Challenge Stability, ecological_interactions#hCom2 Escherichia coli Colonization Resistance
1 evidence item(s)
robust colonization resistance against pathogenic Escherichia coli
Direct abstract evidence for the challenge phenotype; assembly alone is not outcome evidence.
Environmental Factors
| Factor | Value | Unit |
|---|---|---|
| gnotobiotic fecal challenge | Germ-free mice colonized with hCom1 were challenged with a human fecal sample to identify additional engrafting species. | N/A |
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Growth Media
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