Overview
Eubacterium rectale is a strictly anaerobic, Gram-positive bacterium belonging to the family Lachnospiraceae within the phylum Firmicutes. It is one of the most abundant butyrate-producing bacteria in the human colon, playing a fundamental role in colonocyte energy supply, intestinal barrier maintenance, and inflammation suppression. Research consistently identifies E. rectale as depleted in a wide range of inflammatory and immune-mediated conditions, suggesting it may serve as both a biomarker of gut health and a potential therapeutic target.
Classification
E. rectale belongs to the order Eubacteriales within the class Clostridia. It is classified within the Lachnospiraceae family, sharing this taxonomic group with other important SCFA producers such as Roseburia intestinalis and Blautia obeum. The genus Eubacterium is polyphyletic, and some species have been reclassified into other genera; however, E. rectale retains its original designation as a core member of the human gut microbiome.
Key Characteristics
E. rectale produces butyrate as its primary fermentation end product, which serves as the main energy source for colonic epithelial cells. Butyrate production by E. rectale supports intestinal barrier integrity and has been shown to suppress NF-kB-mediated inflammatory signaling. The bacterium's metabolic pathways include butanoate metabolism and flagellar assembly, both of which are significantly enriched in healthy individuals compared to those with inflammatory conditions. The type strain ATCC 33656 has a fully sequenced genome and is widely used in gnotobiotic mouse studies and functional microbiome research.
Health Significance
Depletion of E. rectale has been documented across multiple disease states. In psoriasis and psoriatic arthritis patients, it was identified as the most significantly depleted species, with its associated metabolic functions correspondingly reduced. Preclinical studies suggest that E. rectale may protect against intestinal lymphoma by suppressing TNF-mediated NF-kB signaling through butyrate production, and it may attenuate rheumatoid arthritis by restoring Treg/Tfh immune balance. The genus Eubacterium has also been inversely associated with depression across eight independent studies, suggesting potential gut-brain axis involvement. These findings position E. rectale as a key species for understanding the relationship between gut microbial composition and systemic health, though clinical intervention studies in humans remain limited.