Lachnospira is a genus of Gram-positive, obligate anaerobic bacteria within the Lachnospiraceae family (Firmicutes). L. pectinoschiza, the type species, is a specialist pectin fermenter that produces short chain fatty acids from plant-derived polysaccharides. The genus appears across a wide range of disease association studies with both protective and risk-associated profiles depending on context.
SCFA Production and Fiber Fermentation
- L. pectinoschiza ferments pectin (abundant in fruits, vegetables, and legumes) to acetate, formate, and ethanol.
- This pectin-degrading specialization links Lachnospira abundance directly to dietary fiber intake and plant-rich diets.
- As a member of the Lachnospiraceae family, it contributes to the broader SCFA-producing consortium that maintains gut barrier integrity and modulates immune function.
Depletion in Inflammatory and Cardiovascular Disease
Several studies report reduced Lachnospira in disease states:
- Acute coronary syndrome: depleted in ACS patients post-STEMI compared to healthy controls, while pathobionts like Escherichia-Shigella and acinetobacter were enriched [gao 2020 gut microbial biomarkers acs post stemi].
- Endometriosis: significantly decreased (p=0.00008) in women with endometriosis, consistent with loss of SCFA-producing commensals in inflammatory gynecological conditions [shan 2021 gut microbiota hormone inflammatory endometriosis].
- Thyroid disease: MR evidence identifies Lachnospira as protective against Graves' disease and Plummer disease, likely through SCFA-mediated immune regulation [chen 2024 gut microbiota six thyroid diseases mr].
Risk Associations
Conversely, Lachnospira shows risk associations in other contexts:
- Colorectal cancer: strong MR-identified risk association (OR=4.43) through inflammatory mediators [ma 2024 gut microbiota inflammatory factors crc mr].
- Hidradenitis suppurativa: causal risk factor (OR=2.45) via MR analysis, suggesting a role in skin-gut axis inflammation [liu 2024 gut microbiota hidradenitis suppurativa mr].
- Autism spectrum disorder: significantly more abundant in ASD children in some cohorts [niu 2019 intestinal microbiota probiotics asd china], part of the robust ASD microbiome signature [peralta marzal 2024 robust microbiome signature asd machine learning].
Context-Dependent Effects
The dual nature of Lachnospira -- depleted in cardiovascular and endocrine conditions but enriched or risk-associated in CRC, ASD, and inflammatory skin disease -- reflects the complexity of SCFA-producing commensals. Its effects likely depend on:
- The specific metabolic environment (pectin availability, pH, oxygen gradients)
- Host immune context (immunosuppressive vs. hyperactivated states)
- Interactions with co-occurring microbiota in the Lachnospiraceae network
Connections
- short chain fatty acids -- pectin fermentation to acetate, formate, and ethanol
- cardiovascular disease -- depleted in ACS, protective metabolic role
- endometriosis -- significantly depleted in endometriosis patients
- colorectal cancer -- paradoxical MR risk association despite SCFA production
- autism spectrum disorder -- part of robust ASD microbiome signature
- faecalibacterium prausnitzii -- co-member of the SCFA-producing commensal consortium
- Lachnospiraceae -- family-level context for understanding its ecological role