Overview
Fusicatenibacter is a Gram-positive obligate anaerobic genus within the Lachnospiraceae (Firmicutes). The primary species, F. saccharivorans, was isolated from human feces and is recognized as a beneficial commensal that produces butyrate and modulates intestinal immune responses.
Metal Dependencies
Like other Lachnospiraceae, Fusicatenibacter requires iron for its fermentative enzymes but lacks aggressive iron acquisition systems. This makes it vulnerable to displacement by siderophore-producing Proteobacteria when luminal iron rises during inflammation — a pattern shared with roseburia intestinalis and other butyrate producers.
Ecological Role
F. saccharivorans produces extracellular polysaccharides that suppress pro-inflammatory cytokine production (TNF-alpha, IL-8) by intestinal epithelial cells. This positions it as an active immunomodulator, not merely a passive fermenter. Its butyrate output further supports colonocyte energy metabolism and barrier function. Depletion of Fusicatenibacter may remove a brake on mucosal inflammation.
Conditions Associated
Fusicatenibacter is consistently depleted in inflammatory bowel disease (both Crohn's disease and ulcerative colitis) and colorectal cancer. Its abundance correlates positively with remission in ulcerative colitis patients, making it a potential biomarker for mucosal healing and a candidate for next-generation probiotic development.
Cross-References
- butyrate — metabolic output
- lachnospiraceae — taxonomic family
- iron — competitive vulnerability
- inflammatory bowel disease — depleted in disease