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 bushman 2025 nutrient metals bacteria gut infection.
- 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 khorsand 2022 enterobacteriaceae ecoli ibd ibdmdb metagenomics.
Nickel
- NiFe-hydrogenases (Hya, Hyb, Hyc, Hyd): Oxidize H2 for energy during anaerobic respiration, providing competitive advantage in the inflamed gut maier 2019 nickel microbial pathogenesis.
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 khorsand 2022 enterobacteriaceae ecoli ibd ibdmdb metagenomics wang 2024 ibd integrated 16s metagenomics virulence factors.
- CRC: Enriched in tumor tissue; certain strains produce colibactin (genotoxin) gao 2015 microbiota disbiosis colorectal cancer.
- CVD: Part of Enterobacteriaceae bloom in atherosclerosis jie 2017 gut microbiome acvd.
- ASD: Enriched in gut microbiota of ASD children strati 2017 altered gut microbiota mycobiota asd.
- 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 kaliannan 2018 estrogen gut microbiome metabolic syndrome.
Cross-References
- escherichia coli — species page
- adherent invasive e coli — pathogenic AIEC variant
- shigella — reported together in 16S as Escherichia/Shigella complex
- enterobacteriaceae — family-level context
- iron — siderophore-dependent virulence
- siderophores — enterobactin, salmochelin, aerobactin
- nickel — NiFe-hydrogenase for gut colonization
- estrobolome — beta-glucuronidase activity
- microbial metallomics — curli-amyloid cross-seeding in neurodegeneration