Biology & Ecology
Biology
Gram Statusgram-negative
Oxygen Toleranceobligate anaerobe
Morphologybacillus (rod)
Ecology
Primary Nichesgut
Reservoirhuman
Clinical Profile
Pathobiont
yes
no
context dependent
unknown
Clinical Rolescommensal
Typical Specimenstool
Risk Contextsmelanoma patients receiving immune checkpoint inhibitor therapy (ICB)
Clinical Associations:
E2
E3 — Strong human clinical evidence
E2 — Moderate human evidence
E1 — Limited / preliminary
Bacteroides nordii was enriched in non-responders before FMT in a Phase 2 trial of FMT plus pembrolizumab in 15 PD-1-refractory advanced melanoma patients; transkingdom network analysis identified it as positively correlated with circulating CXCL8 (IL-8), IL-10, and CCL3 — immunosuppressive cytokines associated with poor anti-PD-1 clinical outcomes.
PMID:
33542131
Last reviewed: 2026-04-02
Evidence Timeline
Related Taxa
Shared Niche = same body site
Shared Risk = same vulnerable population
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