Clostridium

Clusters IV and XIVa (Reclassified)#

The dominant Butyrate-producing communities in the healthy human colon, representing up to 40% of total fecal bacteria. Depleted in Multiple Sclerosis: loss reduces SCFA production, impairs Treg differentiation and anti-inflammatory cytokine output.^{[1]Feeding the gut microbiome: impact on multiple sclerosisMatteo Bronzini, Alessandro Maglione, Rachele Rosso et al. · 2023Open reference 1 ↓} Depleted across Crohn's Disease, IBD broadly, Colorectal Cancer, and Cardiovascular Disease.

Induce colonic Tregs via butyrate-HDAC inhibition, a cornerstone of mucosal immune tolerance.

C. butyricum#

Probiotic species used therapeutically in Japan and parts of Asia. Produces butyrate via butyryl-CoA:acetate CoA-transferase pathway. Protective against Clostridioides difficile infection and necrotizing enterocolitis in premature infants.

Enhances gut barrier integrity through butyrate-mediated upregulation of tight junction proteins.

C. perfringens#

Produces at least 20 toxins including alpha-toxin (phospholipase C), beta-toxin, epsilon-toxin, and enterotoxin. Causes gas gangrene, food poisoning, and necrotizing enteritis. Iron-dependent virulence.

C. botulinum#

Produces botulinum neurotoxin, the most potent biological toxin known. The toxin is a Zinc-metalloprotease that cleaves SNARE proteins at neuromuscular junctions.

C. difficile (now [[clostridioides-difficile]])#

Reclassified to Clostridioides. Causes antibiotic-associated diarrhea and pseudomembranous colitis. Opportunistic pathogen that blooms when beneficial Clostridium clusters are depleted by antibiotics.

Metal Dependencies#

Iron: Ferredoxin iron-sulfur clusters are central to clostridial anaerobic metabolism and butyrate synthesis. Iron perturbation in the gut directly affects the metabolic output of beneficial species.

Cobalt: Some species require B12 (cobalamin) for key enzymatic reactions. Zinc: Botulinum toxin is a zinc (Zn)-metalloprotease; C. perfringens phospholipase C also requires metal cofactors. Heavy metal stress Cadmium, Lead preferentially depletes beneficial clostridial clusters while sparing spore-forming pathogenic species, shifting the genus balance toward virulence.

Key Metabolites#

Butyrate—primary SCFA from clusters IV/XIVa; HDAC inhibitor, colonocyte fuel, anti-inflammatory.

Secondary bile acids—7-alpha-dehydroxylation by C. scindens and related species converts primary to secondary bile acids (DCA, LCA), influencing Cardiovascular Disease and CRC risk.^{[2]Bile acids at the cross-roads of gut microbiome-host cardiometabolic interactionsPaul M. Ryan, Catherine Stanton, Noel M. Caplice · 2017Open reference 2 ↓}

Indole derivatives—tryptophan metabolism by some Clostridium species produces AHR ligands with immune-modulatory activity.

Disease Associations#

Clostridium sp. CAG:307 enriched in Endometriosis.^{[3]Gut microbiome in endometriosis: a cohort study on 1000 individualsPerez-Prieto I, Vargas E, Salas-Espejo E et al. · 2024Open reference 3 ↓} CAG9 (Clostridium) negatively correlated with glycerophospholipids in CAD severity analysis.^{[4]Alterations in the gut microbiome and metabolism with coronary artery disease severityHonghong Liu, Xi Chen, Xiaomin Hu et al. · 2019Open reference 4 ↓}

NSAID-induced enteropathy disrupts clostridial communities, reducing protective SCFA output.^{[5]Gut Microbiota in NSAID Enteropathy: New Insights From InsideXianglu Wang, Qiang Tang, Huiqin Hou et al. · 2021Open reference 5 ↓}