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Bacterium

Faecalibacterium prausnitzii

Common name: F. prausnitzii

Beneficial Digestive Gut
Beneficial
Effect
Digestive
Impact
Gut
Location
Very Common
Prevalence
Last reviewed: April 4, 2025

Major butyrate producer with potent anti-inflammatory properties

Prevalence: 5-15% of total gut bacteria in healthy adults; one of the most abundant species

Interacts with: Major butyrate producer, Anti-inflammatory, Desulfovibrio piger symbiosis, Cross-feeding networks

Overview

Scientifically accurate microscopy-style illustration of Faecalibacterium prausnitzii showing its characteristic gram-negative (but with gram-positive-like cell wall) rod-shaped anaerobic bacterium

Faecalibacterium prausnitzii is a Gram-positive, strictly anaerobic, non-spore-forming commensal bacterium that constitutes 5-15% of total gut bacteria in healthy adults, making it one of the most abundant species in the human intestinal microbiota. It has emerged as a cornerstone of gut health due to its potent anti-inflammatory properties and role as a major butyrate producer.[1]

Butyrate Production and Gut Health

F. prausnitzii is a major producer of butyrate, the primary energy source for colonocytes. Butyrate production is responsible for many of the species' beneficial effects:[2]

  • Dact3 pathway: Butyrate upregulates Dact3 gene expression, which negatively regulates Wnt/JNK signaling and blocks IL-8 production
  • SCFA ratios: Shifts SCFA profile toward healthy 3:1:1 ratio (acetate:propionate:butyrate)
  • Gut barrier: Enhances tight junction integrity and mucus layer maintenance
  • HDAC modulation: Influences epigenetic regulation through histone deacetylase inhibition

Anti-Inflammatory Mechanisms

Microbial Anti-inflammatory Molecule (MAM)

A landmark 2016 study identified a 15 kDa protein named MAM (Microbial Anti-inflammatory Molecule) that inhibits NF-κB pathway activation in intestinal epithelial cells in a dose-dependent manner.[3]

Immune Modulation

F. prausnitzii exerts comprehensive immunomodulatory effects:[1]

  • NF-κB inhibition: Blocks NF-κB activation and IL-8 production through secreted metabolites
  • Cytokine profile: Stimulates high IL-10 secretion and low IL-12/IFN-γ in PBMCs
  • Th17 suppression: Inhibits IL-23/Th17/IL-17 pathway
  • Treg induction: Skews dendritic cells to prime IL-10-secreting Tr1-like regulatory T cells
  • TLR2/6 signaling: Activates TLR2/6 and JNK pathway for immune tolerance

Protective Metabolites

Beyond MAM, F. prausnitzii produces other protective compounds:

  • Salicylic acid: Blocks IL-8 production
  • Shikimic acid: Associated with anti-inflammatory effects
  • α-ketoglutarate: Modulates inflammatory pathways

IBD Association

Clinical Evidence

F. prausnitzii abundance is consistently reduced in inflammatory bowel disease:[4]

  • Crohn's disease: Most pronounced reduction, especially with ileal involvement
  • Ulcerative colitis: Significant reduction versus healthy controls
  • Predictive value: Low ileal levels at surgery predict higher risk of endoscopic CD recurrence at 6 months
  • Disease activity: Lower counts associated with increased disease activity and higher relapse rates
  • Remission duration: Lower levels predict shorter clinical remission (<12 months)

DP8α Tregs

A 2022 study discovered that CD4+CD8α+ regulatory T cells (DP8α Tregs) specific to F. prausnitzii protect against intestinal inflammation. Low DP8α cell frequencies in IBD patients are associated with disease activity, flares, and elevated CRP.

Biomarker Potential

F. prausnitzii serves as a biomarker for multiple conditions:[4]

Condition Association
Crohn's disease Significantly reduced; predicts recurrence
Ulcerative colitis Reduced vs healthy controls
Type 2 diabetes Significantly depleted
Chronic kidney disease Depleted in Western and Eastern populations
Cognitive decline/MCI Correlates with cognitive scores
Obesity/metabolic liver disease Reduced; inversely correlated with hepatic fat

Oxygen Sensitivity and Cultivation Challenges

F. prausnitzii is extremely oxygen-sensitive (EOS), creating significant challenges for therapeutic development:

Traditional Limitations

  • Cannot survive standard probiotic manufacturing processes
  • Dies rapidly upon exposure to ambient air
  • Requires strict anaerobic conditions for cultivation

Breakthrough Solutions[5]

A 2023 Nature study achieved major advances:

  • Symbiotic co-culture: Desulfovibrio piger provides acetate and acts as electron sink to promote growth
  • Oxygen adaptation: Stepwise adaptation technology creates oxygen-tolerant strains
  • Industrial production: Enables stable probiotic capsule manufacturing
  • Clinical validation: Human trial (50 participants) showed safety, tolerability, and increased strain abundance

Protective Formulations

  • Cysteine + riboflavin + inulin: Keeps bacterium alive at ambient air for 24 hours
  • Corn starch + wheat bran granules: Achieves 60% viability

Clinical Trials and Therapeutic Applications

Type 2 Diabetes

F. prausnitzii supplementation in diabetic mice decreased fasting blood glucose, improved insulin resistance and glucose intolerance, and ameliorated hepatic steatosis by inhibiting lipogenic enzymes.

Cancer Immunotherapy

High baseline F. prausnitzii in NSCLC and melanoma patients is associated with better ICI response and overall survival. Strain EXL01 restores anti-tumor responses and reduces immunotherapy-induced colitis while enhancing T cell activation.

Chronic Kidney Disease[6]

Supplementation reduces renal dysfunction, inflammation, and fibrosis in mouse models. Effects are mediated by butyrate through renal GPR-43 receptor, with improvements in serum uremic toxins and intestinal barrier integrity.

Obesity and Metabolic Health

Oral administration reduced hepatic fat content, increased fatty acid oxidation, and decreased inflammation in visceral and subcutaneous adipose tissues, with improved insulin sensitivity.

Dietary Modulation

Research shows diet can influence F. prausnitzii levels:

  • Kiwifruit: Supplementation increased abundance from 3.4% to 7.0% in constipated individuals
  • Mediterranean diet: Fiber-rich diet boosts diversity in obese individuals
  • Flavin/riboflavin-rich foods: May support survival at oxic-anoxic interfaces

Documented Strains

A2-165

Faecalibacterium prausnitzii A2-165

Moderate research
DSM 17677
Anti-inflammatory research reference strainIBD biomarker and depletion markerButyrate production referenceNext-generation probiotic candidate

Key Findings

↑

IBD inflammation

Reduced NF-κB activation and IL-8 secretion; blocked experimental colitis in mice

↑

Crohn's disease prediction

Low A2-165 abundance at surgery independently predicts post-operative relapse

The reference strain used in the landmark Sokol 2008 PNAS study establishing F. prausnitzii as an anti-inflammatory commensal — its anti-inflammatory protein MAM (microbial anti-inflammatory molecule) was the first F. prausnitzii-specific bioactive identified, and A2-165 remains the most mechanistically characterised strain of this critically important species

ATCC 27766

Faecalibacterium prausnitzii ATCC 27766

Moderate research
ATCC 27766
Type strain referenceOxygen tolerance researchPhylogroup I representative

Key Findings

↑

Next-generation probiotic development

First F. prausnitzii strain to demonstrate oxygen tolerance enabling commercial-scale production

The international reference type strain for the species — recently demonstrated by Nature (2023) to survive brief oxygen exposure through unique electron transport mechanisms, unlocking the first viable production protocols for a stable F. prausnitzii probiotic product; represents a critical milestone toward the first next-generation probiotic targeting IBD and metabolic disease

HTF-F

Faecalibacterium prausnitzii HTF-F

Preclinical research
IBD/intestinal inflammationDSS-induced colitisExtracellular polymeric matrix (EPM) for mucosal anti-inflammatory therapy

Key Findings

↑

IBD (preclinical)

Significantly decreased colon damage score vs colitis control; more effective than A2-165 in vivo

HTF-F is a biofilm-forming strain that produces an extracellular polymeric matrix (EPM) with independent TLR2-dependent anti-inflammatory activity — a property absent from the type strain A2-165; the EPM itself is a potential drug candidate for IBD

M21/2

Faecalibacterium prausnitzii M21/2

Preclinical research
Reference strain for SCFA production characterizationButyrate production research

Key Findings

↑

SCFA/butyrate research

Distinct butyrate production profile from A2-165; reference for species metabolic diversity

Research reference strain showing different butyrate production kinetics and substrate preferences vs A2-165, supporting strain-level heterogeneity in this species' key function

Associated Conditions

→ Type 2 Diabetes → Obesity → Colorectal Cancer → Cognitive decline

Related Organisms

B
Bacillus cereus Digestive
B
Bacillus coagulans Digestive
B
Bacillus subtilis Digestive
B
Bacteroides dorei Digestive
B
Bacteroides fragilis Digestive
B
Bacteroides thetaiotaomicron Digestive

Frequently Asked Questions

What is Faecalibacterium prausnitzii?

Faecalibacterium prausnitzii is a bacterium found in the human microbiome.

Where is Faecalibacterium prausnitzii found in the body?

Faecalibacterium prausnitzii is primarily found in the Gut.

What are the health impacts of Faecalibacterium prausnitzii?

Faecalibacterium prausnitzii primarily impacts Digestive and is beneficial for human health.

Research References

  1. Sokol H, Pigneur B, Watterlot L, et al.. Faecalibacterium prausnitzii is an anti-inflammatory commensal bacterium identified by gut microbiota analysis of Crohn disease patients. Proceedings of the National Academy of Sciences. 2008. doi:10.1073/pnas.0804812105 ↩
  2. Lenoir M, Martín R, Torres-Maravilla E, et al.. Butyrate mediates anti-inflammatory effects of Faecalibacterium prausnitzii in intestinal epithelial cells through Dact3. Gut Microbes. 2020. doi:10.1080/19490976.2020.1826748 ↩
  3. Quévrain E, Maubert MA, Michon C, et al.. Identification of an anti-inflammatory protein from Faecalibacterium prausnitzii, a commensal bacterium deficient in Crohn's disease. Gut. 2016. doi:10.1136/gutjnl-2014-307649 ↩
  4. Lopez-Siles M, Duncan SH, Garcia-Gil LJ, Martinez-Medina M. Faecalibacterium prausnitzii: from microbiology to diagnostics and prognostics. The ISME Journal. 2017. doi:10.1038/ismej.2016.176 ↩
  5. Khan MT, Dwibedi C, Sundh D, et al.. Synergy and oxygen adaptation for development of next-generation probiotics. Nature. 2023. doi:10.1038/s41586-023-06378-w ↩
  6. Li HB, Xu ML, Xu XD, et al.. Faecalibacterium prausnitzii Attenuates CKD via Butyrate-Renal GPR43 Axis. Circulation Research. 2022. doi:10.1161/CIRCRESAHA.122.320184 ↩