Enterococcus gallinarum — MCA-BAC-000026

Biology & Ecology

Biology

Gram Statusunknown

Oxygen Tolerancemicroaerophile

Ecology

Primary Nichesgut

Reservoiranimal, human

Metabolites

produces C00463 tryptophan-derived AhR ligands (indoles)

consumes

modifies

Clinical Profile

Pathobiont

yes no context dependent unknown

Clinical Rolescoloniser; opportunistic pathogen

Typical Specimenbiopsy; stool

Bloom Triggers inflammation

Risk Contextsautoimmune hepatitis (AIH); genetic predisposition to autoimmunity; immunocompromised patients; impaired gut barrier function; systemic lupus erythematosus (SLE)

Clinical Associations:

E. gallinarum was detected by species-specific PCR and immunostaining in liver biopsies of 3/3 tested SLE patients and 5/6 tested AIH patients but in 0/6 healthy cadaveric liver donor controls; 16S rDNA sequencing showed Enterococcus spp. predominance in AIH and cirrhosis liver tissues relative to healthy controls (human case-control).

PMID: 29590047

D018988 Bacterial Translocation D019693 Hepatitis, Autoimmune D008099 Liver D008180 Lupus Erythematosus, Systemic H01685 Autoimmune hepatitis H00080 Systemic lupus erythematosus

Serum IgG antibody titers against E. gallinarum whole bacteria and its RNA were significantly elevated in the majority of SLE (n=15) and AIH (n=17) patients versus healthy controls (n=9); anti-E. gallinarum RNA IgG correlated with anti-human RNA autoantibody titers in SLE (R²=0.5132, p=0.0027) and AIH (R²=0.8245, p<0.0001) patients (human case-control).

PMID: 29590047

D001323 Autoantibodies D019693 Hepatitis, Autoimmune D008180 Lupus Erythematosus, Systemic H01685 Autoimmune hepatitis H00080 Systemic lupus erythematosus

Monocolonization of germ-free C57BL/6 mice with E. gallinarum (n=4–10) induced gut barrier leakage, translocation to mesenteric veins, MLNs, and liver, and elevated anti-RNA IgG and anti-dsDNA IgG autoantibodies at 8 weeks (p<0.05 to p<0.001 vs. GF); neither E. faecalis nor B. thetaiotaomicron monocolonization induced autoantibodies under the same conditions.

PMID: 29590047

D001323 Autoantibodies D015551 Autoimmunity D018988 Bacterial Translocation

E. gallinarum monocolonization of GF C57BL/6 mice induced marked Th17 expansion in the small intestinal lamina propria (20.1% IL-17A+ vs. 0.50% GF, p<0.0001) and mesenteric lymph nodes (15.1% vs. 0.035%, p<0.001); Th17 expansion was absent in E. faecalis- and B. thetaiotaomicron-monocolonized mice (n=5 per group).

PMID: 29590047

D015551 Autoimmunity D058504 Th17 Cells

E. gallinarum lysate or RNA co-cultured with autoimmune-prone (NZW×BXSB)F1 hepatocytes induced expression of autoantigens ERV gp70 (~15-fold) and β2-glycoprotein I (~3-fold), type I IFN-α (~30-fold), and the AhR/CYP1A1 pathway significantly above induction by E. faecalis or B. thetaiotaomicron (ANOVA, p<0.05 to p<0.0001, n=3 each); the same pattern was replicated in primary human hepatocytes.

PMID: 29590047

D015551 Autoimmunity D022781 Hepatocytes D018336 Receptors, Aryl Hydrocarbon

Administration of the AhR antagonist CH223191 to autoimmune-prone (NZW×BXSB)F1 mice gavaged with E. gallinarum significantly reduced serum anti-RNA IgG (p<0.001) and anti-dsDNA IgG (p<0.001) vs. untreated E. gallinarum-gavaged mice (n=4 per group), confirming that the AhR pathway mediates E. gallinarum-driven autoantibody induction.

PMID: 29590047

D001323 Autoantibodies D015551 Autoimmunity D018336 Receptors, Aryl Hydrocarbon

Oral vancomycin or ampicillin treatment of autoimmune-prone (NZW×BXSB)F1 mice (n=15 per group) prevented mortality, suppressed E. gallinarum translocation to mesenteric veins, MLNs, and liver, and eliminated anti-dsDNA IgG, anti-RNA IgG, anti-β2GPI IgG autoantibodies and Th17/Tfh cell expansion vs. untreated controls (p<0.05 to p<0.0001); neomycin was less effective and metronidazole had no significant effect on survival.

PMID: 29590047

D000900 Anti-Bacterial Agents D001323 Autoantibodies D018988 Bacterial Translocation

Intramuscular vaccination with heat-killed E. gallinarum in autoimmune-prone (NZW×BXSB)F1 mice reduced serum autoantibody levels, prolonged survival, and prevented translocation to internal organs; vaccination against E. faecalis or B. thetaiotaomicron had no protective effect, indicating specificity of the E. gallinarum-driven autoimmune response.

PMID: 29590047

D001327 Autoimmune Diseases D015551 Autoimmunity D001428 Bacterial Vaccines

Enterococcus gallinarum undergoes within-host evolution into mucosally-adapted lineages that exhibit significantly increased translocation to the mesenteric lymph nodes and liver compared to luminal lineages in germ-free monocolonised mice.

PMID: 35831502

D018988 Bacterial Translocation D008099 Liver

Enterococcus gallinarum mucosally-adapted liver isolates exhibit significantly increased resistance to lysozyme-mediated growth inhibition, cathelicidin-related antimicrobial peptide (mCRAMP) killing, and macrophage phagocytosis compared to luminal faecal isolates in vitro.

PMID: 35831502

D054884 Host-Pathogen Interactions

Enterococcus gallinarum liver-adapted isolates induce increased intestinal permeability and reduced epithelial barrier defences, including decreased mucus production, reduced intraepithelial lymphocyte recruitment, and altered tight junction protein expression, in germ-free monocolonised mice.

PMID: 35831502

D007413 Intestinal Mucosa

Enterococcus gallinarum liver-adapted isolates induce increased hepatic inflammatory gene expression, including upregulation of pro-inflammatory cytokines, interferon-stimulated genes, serum amyloid A proteins, and collagen, compared to faecal isolates in germ-free monocolonised mice.

PMID: 35831502

D007249 Inflammation D008099 Liver

Enterococcus gallinarum translocation to the liver exacerbates lupus-like autoimmune manifestations including hepatosplenomegaly, proteinuria, and elevated anti-dsDNA autoantibodies in a TLR7 agonist (imiquimod)-induced autoimmunity mouse model.

PMID: 35831502

D008180 Lupus Erythematosus, Systemic H00080 Systemic lupus erythematosus

Enterococcus gallinarum mucosally-adapted isolates produce an enhanced capsular polysaccharide layer that facilitates evasion of innate immune recognition and is associated with increased liver translocation in germ-free monocolonised mice.

PMID: 35831502

D054884 Host-Pathogen Interactions

Enterococcus gallinarum has been detected in liver biopsies from patients with autoimmune hepatitis and primary sclerosing cholangitis, as reported in prior studies cited by the authors; this finding motivated the in vivo translocation experiments in this paper.

PMID: 35831502

D015209 Cholangitis, Sclerosing D019693 Hepatitis, Autoimmune H01685 Autoimmune hepatitis H01684 Primary sclerosing cholangitis

Last reviewed: 2026-04-02

Evidence Timeline

2018 mixed: animal model (germ-free mouse monocolonization) + human case-control 2022 animal model

Related Taxa Shared Niche = same body site Shared Risk = same vulnerable population ⓘ