Butyricicoccus

A genus of Gram-positive, strictly anaerobic, butyrate-producing bacteria in the order Clostridiales (phylum Firmicutes). The type species, Butyricicoccus pullicaecorum, was originally isolated from chicken caecal content but has since been identified as a significant member of the healthy human gut microbiome. Butyricicoccus has attracted attention as a candidate next-generation probiotic because of its consistent depletion in colorectal cancer, multiple sclerosis, and inflammatory bowel disease — conditions characterized by impaired butyrate production and compromised gut barrier integrity.

Metal Dependencies

As a strictly anaerobic Firmicute, Butyricicoccus requires iron for iron-sulfur cluster enzymes involved in its anaerobic metabolic pathways, including the butyrate production pathway. The genus has not been characterized at the detailed metallomic level. <!— NEEDS VERIFICATION: direct metallomic characterization of Butyricicoccus not yet published —>

Key Enzymes and Virulence Factors

Butyricicoccus is not pathogenic. Its significance is entirely beneficial:

  • Butyryl-CoA dehydrogenase — Key enzyme in the butyrate biosynthesis pathway via the acetyl-CoA route
  • Butyrate kinase — Terminal enzyme in the butyrate kinase pathway for butyrate production
  • Short-chain fatty acid production — Butyrate is the primary metabolic output, serving as the preferred energy source for colonocytes and a potent anti-inflammatory signaling molecule

Ecological Role

Butyrate Production and Barrier Integrity

Butyricicoccus contributes to the pool of gut butyrate producers alongside Faecalibacterium prausnitzii, Roseburia, and other Clostridiales. Butyrate serves multiple protective functions: fueling colonocyte metabolism, maintaining tight junction integrity, suppressing NF-kB-mediated inflammation, and promoting regulatory T cell differentiation. The loss of Butyricicoccus and other butyrate producers is a recurring feature of conditions marked by barrier breakdown and chronic inflammation.

Oral-Gut Presence

Butyricicoccus has been detected in oral microbiome studies, suggesting it may participate in the oral-gut axis. In multiple sclerosis, it is among the taxa altered in the oral microbiome alongside other Gram-positive early colonizers (fitzjerrells 2025 oral dysbiosis hypotaurine ms, case-control, n=100).

Conditions Associated

  • Colorectal cancer — Depleted in CRC patients across multiple studies. In a systematic review of microbial markers for colorectal neoplasia, butyrate-producing taxa including Butyricicoccus are consistently reduced in tumor-bearing patients (yu 2022 systematic review microbial markers colorectal neoplasia, systematic-review-meta-analysis). Multi-omic profiling confirms depletion of butyrate producers in CRC with corresponding enrichment of pathogenic taxa like Fusobacterium nucleatum and Bacteroides fragilis (zou 2024 multi omic microbiome genome transcriptome crc, cross-sectional, n=41).
  • Multiple sclerosis — Altered in the oral microbiome of relapsing-remitting MS patients, with MS showing a broad shift away from Gram-positive early colonizers toward Gram-negative pathobionts (fitzjerrells 2025 oral dysbiosis hypotaurine ms, case-control, n=100).
  • Inflammatory bowel disease — Reduced as part of the general loss of butyrate-producing Firmicutes in IBD.

Key Studies

Cross-References

  • butyrate — Primary metabolic product; loss of production linked to disease progression
  • colorectal cancer — Consistent depletion across CRC microbiome signatures
  • multiple sclerosis — Oral microbiome alteration pattern
  • faecalibacterium prausnitzii — Fellow butyrate producer; co-depleted in multiple conditions
  • roseburia — Fellow butyrate producer in the Clostridiales order
  • dysbiosis — Butyricicoccus loss as marker of impaired butyrate ecology
  • gut microbiome — Candidate next-generation probiotic for butyrate restoration

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