Bacteroidales

Bacteroidales is an order of obligate anaerobic, Gram-negative bacteria within the phylum Bacteroidetes. It includes the families Bacteroidaceae (bacteroides), Prevotellaceae (prevotella), Rikenellaceae, and Porphyromonadaceae (porphyromonas). Bacteroidales are among the most abundant gut commensals, specializing in complex polysaccharide degradation via their signature polysaccharide utilization loci (PULs).

Ecological Role

  • Fiber fermentation: Bacteroidales encode extensive PUL systems for degrading dietary fiber, resistant starch, and host-derived glycans (mucin) — making them the primary fiber-fermenting order in the gut.
  • SCFA production: Major producers of propionate and acetate (less butyrate than Firmicutes).
  • Bile acid metabolism: Bacteroidales possess bile salt hydrolases that deconjugate primary bile acids.
  • Diet-responsive: Mediterranean and fiber-rich diets increase Bacteroidales abundance [1] [2].

Disease Associations

  • T1D: Altered Bacteroidales in autoimmune beta-cell destruction [3].
  • CRC: Immunotherapy response (PD-1 blockade) associated with Bacteroidales abundance [4].
  • CKD: Dietary fiber modulates Bacteroidales and downstream metabolome [5].

Cross-References

References (5)

  1. Adriel Latorre-Pérez, Marta Hernández, Jose Ramón Iglesias et al. (2021). Latorre-Pérez 2021 — The Spanish Gut Microbiome Reveals Links Between Microorganisms and Mediterranean Diet. Scientific Reports. doi:10.1038/s41598-021-01002-1
  2. Fiona C. Ross, Dhrati Patangia, Ghjuvan Grimaud et al. (2024). The interplay between diet and the gut microbiome: implications for health and disease. Nature Reviews Microbiology
  3. Jarno Honkanen, Arja Vuorela, Daniel Muthas et al. (2020). Honkanen 2020 — Fungal Dysbiosis and Intestinal Inflammation in Children with Beta-Cell Autoimmunity. Frontiers in Immunology. doi:10.3389/fimmu.2020.00468
  4. Xinjian Xu, Ji Lv, Fang Guo et al. (2020). Gut Microbiome Influences the Efficacy of PD-1 Antibody Immunotherapy on MSS-Type Colorectal Cancer via Metabolic Pathway. Frontiers in Microbiology. doi:10.3389/fmicb.2020.00814
  5. Jean A. Hall, Matthew I. Jackson, Dennis E. Jewell et al. (2020). Hall et al. 2020 — CKD in Cats Alters Response of the Plasma Metabolome and Fecal Microbiome to Dietary Fiber. PLOS ONE. doi:10.1371/journal.pone.0235480

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