Escherichia

Escherichia is a genus of Gram-negative, facultatively anaerobic bacteria in the Enterobacteriaceae family. The primary species E. coli is simultaneously the most studied bacterium in biology and one of the most consistently enriched organisms in disease-associated microbiomes. In 16S rRNA studies, Escherichia is inseparable from shigella and reported as the Escherichia/Shigella complex — the single most reliable marker of gut dysbiosis across conditions in this wiki (230+ source mentions).

For the species page, see escherichia coli. For the pathogenic variant, see adherent invasive e coli.

Metal Dependencies

Iron — Siderophore Arsenal

Escherichia possesses the most comprehensive iron acquisition toolkit among enteric bacteria:

  • Enterobactin: Kd ~10^-49 M — the strongest iron chelator known. Countered by host lipocalin 2 [1].
  • Salmochelin: Glucosylated enterobactin evading lipocalin-2 (in UPEC and some intestinal strains).
  • Aerobactin: Hydroxamate siderophore providing backup iron acquisition.
  • Yersiniabactin: Dual iron/nickel metallophore (in pathogenic strains).
  • Feo system: Ferrous iron transport under anaerobic conditions.

Inflammation-driven hepcidin elevation sequesters systemic iron but floods the gut lumen with unabsorbed dietary iron — selectively favoring Escherichia expansion via siderophore advantage [2].

Nickel

  • NiFe-hydrogenases (Hya, Hyb, Hyc, Hyd): Oxidize H2 for energy during anaerobic respiration, providing competitive advantage in the inflamed gut [3].

The Universal Dysbiosis Bloom

Escherichia/Shigella enrichment is the single most reproducible microbiome finding across disease states:

  • IBD: Enriched in both Crohn's and UC; AIEC strains colonize ileal mucosa [2] [4].
  • CRC: Enriched in tumor tissue; certain strains produce colibactin (genotoxin) [5].
  • CVD: Part of Enterobacteriaceae bloom in atherosclerosis [6].
  • ASD: Enriched in gut microbiota of ASD children [7].
  • Neurodegeneration: Produces curli amyloid fibers (CsgA) that cross-seed amyloid-beta aggregation — a direct microbial-to-neurodegeneration pathway (see microbial metallomics).
  • Estrogen recirculation: Possesses beta-glucuronidase activity, deconjugating estrogens in the gut and contributing to the estrobolome [8].

Cross-References

References (8)

  1. Summer D Bushman, Eric P Skaar, N Luisa Hiller (2025). Bushman 2025 — The Exploitation of Nutrient Metals by Bacteria for Survival and Infection in the Gut. PLOS Pathogens
  2. Babak Khorsand, Hamid Asadzadeh Aghdaei, Ehsan Nazemalhosseini-Mojarad et al. (2022). Khorsand 2022 — Overrepresentation of Enterobacteriaceae and Escherichia coli is the major gut microbiome signature in Crohn's and UC: comprehensive metagenomic analysis of IBDMDB datasets. Frontiers in Cellular and Infection Microbiology. doi:10.3389/fcimb.2022.1015890
  3. ★Robert J. Maier, Stéphane L. Benoit (2019). Role of Nickel in Microbial Pathogenesis. Inorganics. doi:10.3390/inorganics7070080
  4. Haijing Wang, Yuanjun Wang, Libin Yang et al. (2024). Wang 2024 — Integrated 16S rRNA sequencing and metagenomics insights into microbial dysbiosis and distinct virulence factors in inflammatory bowel disease. Frontiers in Microbiology. doi:10.3389/fmicb.2024.1375804
  5. Zhiguang Gao, Bomin Guo, Renyuan Gao et al. (2015). Microbiota disbiosis is associated with colorectal cancer. Frontiers in Microbiology. doi:10.3389/fmicb.2015.00020
  6. Zhuye Jie, Huihua Xia, Shi-Long Zhong et al. (2017). The gut microbiome in atherosclerotic cardiovascular disease. Nature Communications. doi:10.1038/s41467-017-00900-1
  7. Francesco Strati, Duccio Cavalieri, Davide Albanese et al. (2017). Strati 2017 — New Evidences on the Altered Gut Microbiota in Autism Spectrum Disorders. Microbiome. doi:10.1186/s40168-017-0242-1
  8. Kanakaraju Kaliannan, Ruairi C. Robertson, Kiera Murphy et al. (2018). Kaliannan et al. 2018 — Estrogen-Mediated Gut Microbiome Alterations Influence Sexual Dimorphism in Metabolic Syndrome in Mice. Microbiome. doi:10.1186/s40168-018-0587-0

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