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Characteristics of All the Members of the Family Enterobacteriaceae Include

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Family unit of bacteria

Enterobacteriaceae
Citrobacter freundii.jpg
Citrobacter freundii, one member of the family
Scientific classification e
Domain: Bacteria
Phylum: Proteobacteria
Class: Gammaproteobacteria
Order: Enterobacterales
Family unit: Enterobacteriaceae
Rahn, 1937
Genera[1]

See text

Enterobacteriaceae is a large family of Gram-negative bacteria. It was first proposed by Rahn in 1936, and at present includes over 30 genera and more than 100 species. Its classification above the level of family is all the same a discipline of contend, but one classification places it in the order Enterobacterales of the class Gammaproteobacteria in the phylum Proteobacteria.[ii] [3] [4] [5] In 2016, the clarification and members of this family were emended based on comparative genomic analyses by Adeolu et al.[vi]

Enterobacteriaceae includes, along with many harmless symbionts, many of the more familiar pathogens, such as Salmonella, Escherichia coli, Klebsiella, and Shigella. Other disease-causing bacteria in this family unit include Enterobacter and Citrobacter. Members of the Enterobacteriaceae can be trivially referred to as enterobacteria or "enteric leaner",[seven] every bit several members live in the intestines of animals. In fact, the etymology of the family is enterobacterium with the suffix to designate a family (aceae)—not afterwards the genus Enterobacter (which would be "Enterobacteraceae")—and the type genus is Escherichia.

Morphology [edit]

Members of the Enterobacteriaceae are bacilli (rod-shaped), and are typically 1–5 μm in length. They typically appear every bit medium to large-sized grey colonies on blood agar, although some can express pigments.

Well-nigh have many flagella used to move virtually, but a few genera are nonmotile. Most members of Enterobacteriaceae take peritrichous, type I fimbriae involved in the adhesion of the bacterial cells to their hosts.

They are not spore-forming.

Metabolism [edit]

Similar other proteobacteria, Enterobactericeae take Gram-negative stains,[8] and they are facultative anaerobes, fermenting sugars to produce lactic acid and various other stop products. Near likewise reduce nitrate to nitrite, although exceptions exist. Dissimilar most similar leaner, Enterobacteriaceae generally lack cytochrome c oxidase, there are exceptions.

Catalase reactions vary among Enterobacteriaceae.

Ecology [edit]

Many members of this family are normal members of the gut microbiota in humans and other animals, while others are found in h2o or soil, or are parasites on a variety of different animals and plants.

Model organisms and medical relevance [edit]

Escherichia coli is one of the most important model organisms, and its genetics and biochemistry have been closely studied.

Some enterobacteria are important pathogens, e.1000. Salmonella, or Shigella eastward.g. because they produce endotoxins. Endotoxins reside in the prison cell wall and are released when the cell dies and the jail cell wall disintegrates. Some members of the Enterobacteriaceae produce endotoxins that, when released into the bloodstream following cell lysis, cause a systemic inflammatory and vasodilatory response. The most severe grade of this is known equally endotoxic daze, which tin can be rapidly fatal.

Historical systematics and taxonomy [edit]

Enterobacteriaceae was originally the sole family nether the lodge 'Enterobacteriales'. The family unit contained a large assortment of biochemically singled-out species with different ecological niches, which made biochemical descriptions hard.[9] [ten] The original classification of species to this family and gild was largely based on 16S rRNA genome sequence analyses, which is known to have low discriminatory power and the results of which changes depends on the algorithm and organism information used. Despite this, the analyses nevertheless exhibited polyphyletic branching, indicating the presence of distinct subgroups inside the family.[11]

In 2016, the gild 'Enterobacteriales' was renamed to Enterobacterales, and divided into 7 new families, including the emended Enterobacteriaceae family unit.[6] This emendation restricted the family to include only those genera directly related to the type genus, which included nearly of the enteric species nether the order. This classification was proposed based on the construction of several robust phylogenetic trees using conserved genome sequences, 16S rRNA sequences and multilocus sequence analyses. Molecular markers, specifically conserved signature indels, specific to this family unit were identified as evidence supporting the division independent of phylogenetic trees.

In 2017, a subsequent study using comparative phylogenomic analyses identified the presence of 6 subfamily level clades within the family unit Enterobacteriaceae, namely the "Escherichia clade", "Klebsiella clade", "Enterobacter clade", "Kosakonia clade", "Cronobacter clade", "Cedecea clade" and a "Enterobacteriaceae incertae sedis clade" containing species whose taxonomic placement within the family is unclear.[12] Yet, this division was non officially proposed as the subfamily rank is more often than not not used.

Molecular signatures [edit]

Analyses of genome sequences from Enterobacteriaceae species identified 21 conserved signature indels (CSIs) that are uniquely present in this family in the proteins NADH:ubiquinone oxidoreductase (subunit K), twitching move protein PilT, ii,3-dihydroxybenzoate-AMP ligase, ATP/GTP-bounden poly peptide, multifunctional fatty acid oxidation circuitous (subunit alpha), Due south-formylglutathione hydrolase, aspartate-semialdehyde dehydrogenase, epimerase, membrane poly peptide, formate dehydrogenylase (subunit 7), glutathione South-transferase, major facilitator superfamily transporter, phosphoglucosamine mutase, glycosyl hydrolase 1 family protein, 23S rrna [uracil(1939)-C(5)]-methyltransferase, co-chaperone HscB, North-acetylmuramoyl-L-alanine amidase, sulfate ABC transporter ATP-bounden protein CysA, and LPS associates protein LptD.[6] These CSIs provide a molecular means of distinguishing Enterobacteriaceae from other families within the order Enterobacterales and other bacteria.

Genera [edit]

Validly published genera [edit]

The post-obit genera have been validly published, thus they have "Standing in Nomenclature". The yr the genus was proposed is listed in parentheses after the genus name.

  • Biostraticola (2008)
  • Buttiauxella (1982)
  • Cedecea (1981)
  • Citrobacter (1932)
  • Cronobacter (2008)
  • Enterobacillus (2015)
  • Enterobacter (1960)
  • Escherichia (1919)
  • Franconibacter (2014)
  • Gibbsiella (2011)
  • Izhakiella (2016)
  • Klebsiella (1885)
  • Kluyvera (1981)
  • Kosakonia (2013)
  • Leclercia (1987)
  • Lelliottia (2013)
  • Limnobaculum (2018)
  • Mangrovibacter (2010)
  • Metakosakonia (2017)
  • Phytobacter (2017)
  • Pluralibacter (2013)
  • Pseudescherichia (2017)
  • Pseudocitrobacter (2014)
  • Raoultella (2001)
  • Rosenbergiella (2013)
  • Saccharobacter (1990)
  • Salmonella (1900)
  • Scandinavium (2020)
  • Shigella (1919)
  • Shimwellia (2010)
  • Siccibacter (2014)
  • Trabulsiella (1992)
  • Yokenella (1985)

Candidatus genera [edit]

  • "Candidatus Annandia"
  • "Candidatus Arocatia"
  • "Candidatus Aschnera"
  • "Candidatus Benitsuchiphilus"
  • "Candidatus Blochmannia"
  • "Candidatus Curculioniphilus"
  • "Candidatus Cuticobacterium"
  • "Candidatus Doolittlea"
  • "Candidatus Gillettellia"
  • "Candidatus Gullanella"
  • "Candidatus Hamiltonella"
  • "Candidatus Hartigia"
  • "Candidatus Hoaglandella"
  • "Candidatus Ischnodemia"
  • "Candidatus Ishikawaella"
  • "Candidatus Kleidoceria"
  • "Candidatus Kotejella"
  • "Candidatus Macropleicola"
  • "Candidatus Mikella"
  • "Candidatus Moranella"
  • "Candidatus Phlomobacter"
  • "Candidatus Profftia"
  • "Candidatus Purcelliella"
  • "Candidatus Regiella"
  • "Candidatus Riesia"
  • "Candidatus Rohrkolberia"
  • "Candidatus Rosenkranzia"
  • "Candidatus Schneideria"
  • "Candidatus Stammera"
  • "Candidatus Stammerula"
  • "Candidatus Tachikawaea"
  • "Candidatus Westeberhardia"

Proposed genera [edit]

The following genera have been effectively, but not validly, published, thus they do non have "Standing in Classification". The year the genus was proposed is listed in parentheses after the genus name.

  • Aquamonas (2009)
  • Atlantibacter (2016)
  • Superficieibacter (2018)

Identification [edit]

To place different genera of Enterobacteriaceae, a microbiologist may run a series of tests in the lab. These include:[13]

  • Phenol red
  • Tryptone broth
  • Phenylalanine agar for detection of production of deaminase, which converts phenylalanine to phenylpyruvic acid
  • Methyl blood-red or Voges-Proskauer tests depend on the digestion of glucose. The methyl red tests for acid endproducts. The Voges Proskauer tests for the production of acetylmethylcarbinol.
  • Catalase test on food agar tests for the product of enzyme catalase, which splits hydrogen peroxide and releases oxygen gas.
  • Oxidase test on nutrient agar tests for the production of the enzyme oxidase, which reacts with an aromatic amine to produce a purple color.
  • Nutrient gelatin tests to discover action of the enzyme gelatinase.

In a clinical setting, iii species brand upward 80 to 95% of all isolates identified. These are Escherichia coli, Klebsiella pneumoniae, and Proteus mirabilis. Still, Proteus mirabilis is now considered a part of the Morganellaceae, a sister clade within the Enterobacterales.

Antibody resistance [edit]

Several Enterobacteriaceae strains have been isolated which are resistant to antibiotics including carbapenems, which are frequently claimed as "the last line of antibody defense" against resistant organisms. For instance, some Klebsiella pneumoniae strains are carbapenem resistant.[xiv] Various carbapenemases genes (blaOXA-48, blaKPC and blaNDM-1, blaVIM and blaIMP) take been identified in carbapenem resistant Enterobacteriaceae including Escherichia coli and Klebsiella pneumoniae.[15]

References [edit]

  1. ^ "List of genera included in families - Enterobacteriaceae". List of Prokaryotic Names with Standing in Nomenclature. Retrieved 26 June 2016.
  2. ^ Don J. Brenner; Noel R. Krieg; James T. Staley (July 26, 2005) [1984 (Williams & Wilkins)]. George Thousand. Garrity (ed.). The Gammaproteobacteria. Bergey's Manual of Systematic Bacteriology. Vol. 2B (2d ed.). New York: Springer. p. 1108. ISBN978-0-387-24144-9. British Library no. GBA561951.
  3. ^ Zipcodezoo site Enterobacteriales Archived 2014-04-27 at the Wayback Machine accessed ix Mar 2013
  4. ^ NCBI Enterobacteriales accessed nine Mar 2013
  5. ^ Taxonomicon Enterobacteriales accessed 9 Mar 2013
  6. ^ a b c Adeolu, 1000; Alnajar, Due south; Naushad, S; South Gupta, R (December 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 Periodical of Systematic and Evolutionary Microbiology. 66 (12): 5575–5599. doi:10.1099/ijsem.0.001485. PMID 27620848.
  7. ^ "Archived copy". Archived from the original on 2011-12-10. Retrieved 2019-01-26 . {{cite web}}: CS1 maint: archived re-create equally championship (link)
  8. ^ "Dorlands Medical Dictionary:Enterobacteriaceae". Archived from the original on 2009-08-28.
  9. ^ Brenner, Don J.; Krieg, Noel R.; Staley, James T.; Garrity, George One thousand.; Boone, David R.; De Vos, Paul; Goodfellow, Michael; Rainey, Fred A.; Schleifer, Karl-Heinz, eds. (2005). Bergey's Manual® of Systematic Bacteriology. doi:10.1007/0-387-28022-vii. ISBN978-0-387-24144-9.
  10. ^ Octavia, Sophie; Lan, Ruiting (2014), "The Family unit Enterobacteriaceae", The Prokaryotes, Berlin, Heidelberg: Springer Berlin Heidelberg, pp. 225–286, doi:10.1007/978-iii-642-38922-1_167, ISBN978-iii-642-38921-4 , retrieved 2021-06-02
  11. ^ Francino, One thousand. Pilar; Santos, Scott R.; Ochman, Howard (2006), "Phylogenetic Relationships of Bacteria with Special Reference to Endosymbionts and Enteric Species", The Prokaryotes, New York, NY: Springer New York, pp. 41–59, doi:10.1007/0-387-30746-x_2, ISBN978-0-387-25496-viii , retrieved 2021-06-02
  12. ^ Alnajar, Seema; Gupta, Radhey S. (October 2017). "Phylogenomics and comparative genomic studies delineate vi master 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. ISSN 1567-7257. PMID 28658607.
  13. ^ MacFaddin, Jean F. Biochemical Tests for Identification of Medical Bacteria. Williams & Wilkins, 1980, p 441.
  14. ^ Centers for Affliction Control and Prevention - Klebsiella Quotation: "Increasingly, Klebsiella bacteria have developed antimicrobial resistance, most recently to the class of antibiotics known every bit carbapenems."
  15. ^ Ghaith, Doaa M.; Mohamed, Zeinat K.; Farahat, Mohamed G.; Aboulkasem Shahin, Walaa; Mohamed, Hadeel O. (March 2019). "Colonization of intestinal microbiota with carbapenemase-producing Enterobacteriaceae in paediatric intensive intendance units in Cairo, Egypt". Arab Journal of Gastroenterology. 20 (1): 19–22. doi:x.1016/j.ajg.2019.01.002. PMID 30733176. S2CID 73444389.

External links [edit]

  • Media related to Enterobacteriaceae at Wikimedia Eatables
  • Enterobacteriaceae genomes and related data at PATRIC, a Bioinformatics Resource Heart funded by NIAID
  • Evaluation of new figurer-enhanced identification plan for microorganisms: adaptation of BioBASE for identification of members of the family Enterobacteriaceae [1]
  • Dark-brown, A.E. (2009). Benson'due south microbiological applications: laboratory manual in general microbiology. New York: McGraw- Hill.

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Source: https://en.wikipedia.org/wiki/Enterobacteriaceae

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