Oscillibacter

Metal Dependencies#

Oscillibacter depends on iron for its anaerobic metabolism. Iron-sulfur cluster proteins are essential for its electron transport chain and fermentation pathways.

This iron dependency makes Oscillibacter vulnerable to toxic metal displacement. Lead exposure (100-500 ppm, 8 weeks) in Balb/C mice significantly decreased Oscillibacter alongside Lachnospiraceae and Ruminococcaceae, with concurrent increases in Oxidative Stress defense pathways (,^{[2]Gut dysbiosis in animals due to environmental chemical exposuresRosenfeld CS · 2017Open reference 2 ↓} animal-model).

Cadmium exposure in wild long-tailed dwarf hamsters significantly decreased Oscillibacter, identifying it as one of 14 potential pathogens/commensals affected by cadmium (Cd) perturbation (,^{[3]Cadmium Exposure Induces Changes in Gut Microbial Composition and Metabolic Function in Long-Tailed Dwarf Hamsters, Cricetulus longicaudatusMengfan Tao, Kanglin Cao, Xinsheng Pu et al. · 2024Open reference 3 ↓} animal-model).

Key Enzymes and Virulence Factors#

Oscillibacter is not pathogenic. Its key metabolic enzymes reflect a saccharolytic fermentation strategy. Valerate synthesis enzymes: The genus's defining metabolic feature is production of valerate from carbohydrate fermentation.

Valerate has immunomodulatory properties and may influence epithelial differentiation, though it is less studied than butyrate.

Butyrate production: Some Oscillibacter species also produce butyrate, contributing to the overall SCFA pool. Bile acid metabolism: Oscillibacter has been implicated in secondary bile acid transformation, linking it to lipid metabolism and cholesterol homeostasis.

Ecological Role#

In the healthy gut, Oscillibacter is a moderately abundant member of the Firmicutes community that contributes to the SCFA pool and bile acid metabolism. Its ecological significance becomes apparent under stress.

Metal exposure indicator: The reproducible depletion of Oscillibacter under both cadmium and lead exposure makes it a candidate biomarker for environmental metal stress on the Gut Microbiome.

Diet-responsive: On a low-carbohydrate, high-fat (non-ketogenic) diet, Oscillibacter was enriched alongside Escherichia/Shigella, and this LCD-associated community worsened colitis outcomes in mice—contrasting with the ketogenic diet, which enriched beneficial Akkermansia and Roseburia instead (,^{[4]Ketogenic Diet Alleviates Colitis by Reduction of Colonic Group 3 Innate Lymphoid Cells Through Altering Gut MicrobiomeKong C, Yan X, Liu Y et al. · 2021Open reference 4 ↓} animal-model).

Metformin response: Oscillibacter increased in both healthy and T2D subjects after metformin treatment (,^{[5]Elbere 2020 — Baseline Gut Microbiome Composition Predicts Metformin Therapy Short-Term Efficacy in Newly Diagnosed Type 2 Diabetes PatientsIlze Elbere, Ivars Silamikelis, Ilze Izabella Dindune et al. · 2020Open reference 5 ↓} prospective-cohort).

Cancer ecology: In CRC tumor tissue, Oscillibacter abundance correlated with steroid biosynthesis and terpenoid pathways (,^{[6]Metabolomics and 16S rRNA Sequencing of Human Colorectal Cancers and Adjacent MucosaLoke MF, Chua EG, Gan HM et al. · 2018Open reference 6 ↓} cross-sectional).

After FMT in CRC mice, Oscillibacter was negatively correlated with anti-cancer cytokines, suggesting its reduction may be beneficial in the tumor microenvironment (,^{[7]Fecal Microbiota Transplantation Inhibits Colorectal Cancer Progression: Reversing Intestinal Microbial Dysbiosis to Enhance Anti-Cancer Immune ResponsesHao Yu, Xing-Xiu Li, Xing Han et al. · 2023Open reference 7 ↓} animal-model).

Depleted in:#

Cadmium exposure: Significantly decreased in wild hamsters exposed to CdCl2, identified among the most affected commensals (,^{[3]Cadmium Exposure Induces Changes in Gut Microbial Composition and Metabolic Function in Long-Tailed Dwarf Hamsters, Cricetulus longicaudatusMengfan Tao, Kanglin Cao, Xinsheng Pu et al. · 2024Open reference 3 ↓} animal-model).

Lead exposure: Decreased alongside Lachnospiraceae and Ruminococcaceae in lead-exposed mice (,^{[2]Gut dysbiosis in animals due to environmental chemical exposuresRosenfeld CS · 2017Open reference 2 ↓} animal-model).

Enriched in:#

Low-carb diet (non-ketogenic): Enriched on LCD but associated with worse colitis outcomes (,^{[4]Ketogenic Diet Alleviates Colitis by Reduction of Colonic Group 3 Innate Lymphoid Cells Through Altering Gut MicrobiomeKong C, Yan X, Liu Y et al. · 2021Open reference 4 ↓} animal-model). Metformin treatment: Increased in both healthy and T2D subjects after metformin (,^{[5]Elbere 2020 — Baseline Gut Microbiome Composition Predicts Metformin Therapy Short-Term Efficacy in Newly Diagnosed Type 2 Diabetes PatientsIlze Elbere, Ivars Silamikelis, Ilze Izabella Dindune et al. · 2020Open reference 5 ↓} prospective-cohort).