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Enterobacteriaceae

From Wikipedia, the free encyclopedia

Enterobacteriaceae
Citrobacter freundii, a member of the family
Scientific classification Edit this classification
Domain: Bacteria
Kingdom: Pseudomonadati
Phylum: Pseudomonadota
Class: Gammaproteobacteria
Order: Enterobacterales
Family: Enterobacteriaceae
Rahn 1937 (Approved Lists 1980)[1]
Type genus
Escherichia
Castellani and Chalmers 1919 (Approved Lists 1980)
Genera[1]

See text

Enterobacteriaceae is a large family of Gram-negative bacteria in the order Enterobacterales. The family includes bacteria found in the gastrointestinal tracts of humans and other animals, as well as species associated with soil, water, plants, and insects.[2] It contains commensal organisms and several medically important genera, including Escherichia, Klebsiella, Salmonella, Shigella, Enterobacter, and Citrobacter.[2] The type genus is Escherichia.[1]

Characteristics

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Members of the family are typically non-spore-forming, straight rods. They are generally facultative anaerobes that ferment glucose, and most reduce nitrate to nitrite and lack cytochrome c oxidase. Motility varies; motile members usually have peritrichous flagella, whereas other members are nonmotile.[3][4]

The outer membrane contains lipopolysaccharide (LPS). Its lipid A component acts as an endotoxin and can provoke a strong inflammatory response; systemic exposure can contribute to septic shock.[5]

Ecology and medical importance

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Members of Enterobacteriaceae occupy diverse ecological niches. Some form part of the normal gut microbiota of humans and other animals, while others occur in freshwater, wastewater, soil, plants, or in association with insects.[2][6]

Escherichia coli is an extensively studied model organism in genetics, biochemistry, and molecular biology.[7] Pathogenic members of the family can cause intestinal or extraintestinal disease, including gastroenteritis, urinary tract infection, pneumonia, bloodstream infection, and meningitis.[2]

Taxonomy

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The family name Enterobacteriaceae was conserved by Judicial Opinion 15, with Escherichia designated as its type genus, even though the family name is not formed from the name of that genus.[8][1]

Enterobacteriaceae was formerly used for a much broader assemblage of bacteria. A genome-based revision established the order Enterobacterales and emended Enterobacteriaceae, while placing many former members in the families Budviciaceae, Erwiniaceae, Hafniaceae, Morganellaceae, Pectobacteriaceae, and Yersiniaceae.[9]

A later comparative genomic analysis divided the family informally into six principal groups named for Escherichia, Klebsiella, Enterobacter, Kosakonia, Cronobacter, and Cedecea, together with an incertae sedis group. These groups were not established as formal subfamilies.[10]

The 2016 genome-based analysis also reported 21 conserved signature indels distributed among 19 proteins in the Enterobacteriaceae taxa examined. These markers, together with phylogenomic analyses, were used to distinguish the family from other lineages within Enterobacterales.[9]

Phylogeny

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The genus-level tree below is based on the GTDB R11-RS232 bacterial reference tree, with genus names following LPSN nomenclature.[1][11][12][13] GTDB includes Shigella within Escherichia; Saccharobacter and Tenebrionicola are omitted because no representatives of their type species were found in this release.

Genus-level phylogeny based on 120 marker proteins (GTDB R11-RS232)[11][12][13]
Enterobacteriaceae

Genera

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The List of Prokaryotic names with Standing in Nomenclature recognizes the following 41 genera with validly published and correct names in Enterobacteriaceae. Synonyms and names without standing in nomenclature are excluded.[1]

Antimicrobial resistance

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Some members of the family, particularly strains of E. coli and Klebsiella pneumoniae, have acquired resistance to carbapenem antibiotics. These organisms are included within the broader public-health category of carbapenem-resistant Enterobacterales (CRE), which is defined at the order level rather than being restricted to Enterobacteriaceae.[14] CRE infections can be difficult to treat because the organisms may also be resistant to other classes of antibiotics.[14]

References

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  1. 1 2 3 4 5 6 "Family: Enterobacteriaceae". List of Prokaryotic names with Standing in Nomenclature. Leibniz Institute DSMZ. Retrieved 16 August 2026.
  2. 1 2 3 4 Janda, J. Michael; Abbott, Sharon L. (2021). "The Changing Face of the Family Enterobacteriaceae (Order: "Enterobacterales"): New Members, Taxonomic Issues, Geographic Expansion, and New Diseases and Disease Syndromes". Clinical Microbiology Reviews. 34 (2) e00174-20. doi:10.1128/CMR.00174-20. PMC 8262773. PMID 33627443.
  3. ↑ Brenner, Don J.; Farmer, John J. III (2005). "Family I. Enterobacteriaceae Rahn 1937". In Brenner, Don J.; Krieg, Noel R.; Staley, James T. (eds.). Bergey's Manual of Systematic Bacteriology. Vol. 2, Part B: The Gammaproteobacteria (2nd ed.). New York: Springer. pp. 587–607. ISBN 978-0-387-24144-9.
  4. ↑ Cordier, Jean-Louis (2006). "Enterobacteriaceae". Emerging Foodborne Pathogens. Woodhead Publishing. pp. 450–475. doi:10.1533/9781845691394.2.450. ISBN 978-1-85573-963-5.
  5. ↑ Farhana, Aisha; Khan, Yusuf S. (17 April 2023). "Biochemistry, Lipopolysaccharide". StatPearls [Internet]. Treasure Island, Florida: StatPearls Publishing. Retrieved 16 August 2026.
  6. ↑ Wang, Zhiying; Hu, Huifeng; Zhu, Tongbo; Zheng, Jinshui; Gänzle, Michael G.; Simpson, David J. (2021). "Ecology and Function of the Transmissible Locus of Stress Tolerance in Escherichia coli and Plant-Associated Enterobacteriaceae". mSystems. 6 (4) e00378-21. doi:10.1128/mSystems.00378-21. PMC 8407380. PMID 34402641.
  7. ↑ Blount, Zachary D. (2015). "The unexhausted potential of E. coli". eLife. 4 e05826. doi:10.7554/eLife.05826. PMC 4373459. PMID 25807083.
  8. ↑ Judicial Commission of the International Committee on Bacteriological Nomenclature (1958). "Conservation of the family name Enterobacteriaceae, of the name of the type genus, and designation of the type species: Opinion No. 15". International Bulletin of Bacteriological Nomenclature and Taxonomy. 8 (1): 73–74. doi:10.1099/0096266X-8-1-73.
  9. 1 2 Adeolu, Mobolaji; Alnajar, Seema; Naushad, Sohail; Gupta, Radhey S. (2016). "Genome-based phylogeny and taxonomy of the 'Enterobacteriales': proposal for Enterobacterales ord. nov. divided into the families Enterobacteriaceae, Erwiniaceae fam. nov., Pectobacteriaceae fam. nov., Yersiniaceae fam. nov., Hafniaceae fam. nov., Morganellaceae fam. nov., and Budviciaceae fam. nov". International Journal of Systematic and Evolutionary Microbiology. 66 (12): 5575–5599. doi:10.1099/ijsem.0.001485. PMID 27620848.
  10. ↑ Alnajar, Seema; Gupta, Radhey S. (2017). "Phylogenomics and comparative genomic studies delineate six main clades within the family Enterobacteriaceae and support the reclassification of several polyphyletic members of the family". Infection, Genetics and Evolution. 54: 108–127. doi:10.1016/j.meegid.2017.06.024. PMID 28658607.
  11. 1 2 "GTDB R232 statistics". Genome Taxonomy Database. Retrieved 16 August 2026.
  12. 1 2 "About GTDB". Genome Taxonomy Database. Retrieved 16 August 2026.
  13. 1 2 "GTDB R11-RS232 bacterial reference tree" (Newick). Genome Taxonomy Database. Retrieved 16 August 2026.
  14. 1 2 "About Carbapenem-resistant Enterobacterales (CRE)". Centers for Disease Control and Prevention. 17 December 2025. Retrieved 16 August 2026.
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