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Enterobacteriaceae is a large family of Gram-negative bacteria. It was first proposed by Rahn in 1936, and now includes over 30 genera and more than 100 species. Its classification above the level of family is still a subject of debate, but one classification places it in the order Enterobacterales of the class Gammaproteobacteria in the phylum Proteobacteria.
Yersinia is a genus of bacteria in the family Yersiniaceae. Yersinia species are Gram-negative, coccobacilli bacteria, a few micrometers long and fractions of a micrometer in diameter, and are facultative anaerobes. Some members of Yersinia are pathogenic in humans; in particular, Y. pestis is the causative agent of the plague. Rodents are the natural reservoirs of Yersinia; less frequently, other mammals serve as the host. Infection may occur either through blood or in an alimentary fashion, occasionally via consumption of food products contaminated with infected urine or feces.
Enterobacterales with its type genus Enterobacter is an order of Gram-negative bacteria.
Escherichia is a genus of Gram-negative, non-spore-forming, facultatively anaerobic, rod-shaped bacteria from the family Enterobacteriaceae. In those species which are inhabitants of the gastrointestinal tracts of warm-blooded animals, Escherichia species provide a portion of the microbially derived vitamin K for their host. A number of the species of Escherichia are pathogenic. The genus is named after Theodor Escherich, the discoverer of Escherichia coli. Escherichia are facultative aerobes, with both aerobic and anaerobic growth, and an optimum temperature of 37 °C. Escherichia are usually motile by flagella, produce gas from fermentable carbohydrates, and do not decarboxylate lysine or hydrolyze arginine. Species include E. albertii, E. fergusonii, E. hermannii, E. senegalensis, E. marmotae and most notably, the model organism and clinically relevant E. coli. Shimwellia blattae was formerly classified in this genus.
Enterobacter is a genus of common Gram-negative, facultatively anaerobic, rod-shaped, non-spore-forming bacteria of the family Enterobacteriaceae. It is the type genus of the order Enterobacterales. Several strains of these bacteria are pathogenic and cause opportunistic infections in immunocompromised hosts and in those who are on mechanical ventilation. The urinary and respiratory tracts are the most common sites of infection. The genus Enterobacter is a member of the coliform group of bacteria. It does not belong to the fecal coliforms group of bacteria, unlike Escherichia coli, because it is incapable of growth at 44.5 °C in the presence of bile salts. Some of them show quorum sensing properties.
Providencia is genus of Gram-negative, motile bacteria of the family Morganellaceae. It was named after Providence, Rhode Island, where C. A. Stuart and colleagues studied these bacteria at Brown University.
The oxidase test is a test used in microbiology to determine if a bacterium produces certain cytochrome c oxidases. It uses disks impregnated with a reagent such as N,N,N′,N′-tetramethyl-p-phenylenediamine (TMPD) or N,N-dimethyl-p-phenylenediamine (DMPD), which is also a redox indicator. The reagent is a dark-blue to maroon color when oxidized, and colorless when reduced. Oxidase-positive bacteria possess cytochrome oxidase or indophenol oxidase. These both catalyze the transport of electrons from donor compounds (NADH) to electron acceptors . The test reagent, TMPD dihydrochloride acts as an artificial electron donor for the enzyme oxidase. The oxidized reagent forms the colored compound indophenol blue. The cytochrome system is usually only present in aerobic organisms that are capable of using oxygen as the terminal electron acceptor. The end-product of this metabolism is either water or hydrogen peroxide.
Enterobacter cloacae is a clinically significant Gram-negative, facultatively-anaerobic, rod-shaped bacterium.
Pantoea is a genus of Gram-negative bacteria of the family Erwiniaceae, recently separated from the genus Enterobacter. This genus includes at least 20 species. Pantoea bacteria are yellow pigmented, ferment lactose, are motile, and form mucoid colonies. Some species show quorum sensing ability that could drive different gene expression, hence controlling certain physiological activities.
Cronobacter is a genus of Gram-negative, facultatively anaerobic, oxidase-negative, catalase-positive, rod-shaped bacteria of the family Enterobacteriaceae. They are generally motile, reduce nitrate, use citrate, hydrolyze esculin and arginine, and are positive for L-ornithine decarboxylation. Acid is produced from D-glucose, D-sucrose, D-raffinose, D-melibiose, D-cellobiose, D-mannitol, D-mannose, L-rhamnose, L-arabinose, D-trehalose, galacturonate and D-maltose. Cronobacter spp. are also generally positive for acetoin production and negative for the methyl red test, indicating 2,3-butanediol rather than mixed acid fermentation. The type species of the genus Cronobacter is Cronobacter sakazakii comb. nov.
Cedecea is a genus of extremely rare bacteria of the family Enterobacteriaceae. The name of this genus was derived from CDC, the abbreviation for the Centers for Disease Control where the initial members of this genus were discovered. This genus resembles no other group of Enterobacteriaceae. Cedecea bacteria are Gram-negative, bacillus in shape, motile, nonencapsulated, and non-spore-forming. The strains of Cedecea appear to be similar to those of Serratia. Both Cedecea and Serratia are lipase positive and resistant to colistin and cephalothin; however, Cedecea is unable to hydrolyze gelatin or DNA.
Enhydrobacter is a genus of bacteria which belongs to the class Alphaproteobacteria. So far, only one species is known. Enhydrobacter has been discussed to be reclassified to the family Rhodospirillaceae and the class Alphaproteobacteria. Because of its oxidase positive it can not be placed in the family Enterobacteriaceae as it is not a parasite of birds or mammals.
Samsonia is a genus of Gram-negative bacteria in the family Yersiniaceae. Species within this genus were originally found in the bark of diseased Erythrina trees. Among bacterial plant pathogens within the Enterobacterales, Samsonia species may be most closely related to Pectobacterium species. Until now, only one species of this genus has been described.
Shimwellia is a genus of Gram-negative bacteria of the family Enterobacteriaceae. The two species of Shimwellia are Shimwellia blattae and Shimwellia pseudoproteus.
The Yersiniaceae are a family of Gram-negative bacteria that includes some familiar pathogens. For example, the type genus Yersinia includes Yersinia pestis, the causative agent of plague. This family is a member of the order Enterobacterales in the class Gammaproteobacteria of the phylum Proteobacteria. Other genera in this family include Chania, Chimaeribacter, Ewingella, Nissabacter, Rahnella, Rouxiella, Samsonia, Serratia, and "Candidatus Fukatsuia".
Phytobacter is a genus of Gram-negative bacteria emerging from the grouping of isolates previously assigned to various genera of the family Enterobacteriaceae. This genus was first established on the basis of nitrogen fixing isolates from wild rice in China, but also includes a number of isolates obtained during a 2013 multi-state sepsis outbreak in Brazil and, retrospectively, several clinical strains isolated in the 1970s in the United States that are still available in culture collections, which originally were grouped into Brenner's biotype XII. Standard biochemical evaluation panels are lacking Phytobacter spp. from their database, thus often leading to misidentifications with other Enterobacterales species, especially Pantoea agglomerans. Clinical isolates of the species have been identified as an important source of extended-spectrum β-lactamase and carbapenem-resistance genes, which are usually mediated by genetic mobile elements. Strong protection of co-infecting sensitive bacteria has also been reported. Bacteria belonging to this genus are not pigmented, chemoorganotrophic and able to fix nitrogen. They are lactose fermenting, cytochrome-oxidase negative and catalase positive. Glucose is fermented with the production of gas. Colonies growing on MacConkey agar (MAC) are circular, convex and smooth with non-entire margins and an usually elevated center. Three species are currently validly included in the genus Phytobacter, which is still included within the Kosakonia clade in the lately reviewed family of Enterobacteriaceae. The incorporation of a fourth species, Phytobacter massiliensis, has recently been proposed via the unification of the genera Metakosakonia and Phytobacter.
The Pectobacteriaceae are a family of Gram-negative bacteria which largely consist of plant pathogens. This family is a member of the order Enterobacterales in the class Gammaproteobacteria of the phylum Proteobacteria. Genera in this family include the type genus Pectobacterium, along with Brenneria, Dickeya, Lonsdalea, and Sodalis.
The Hafniaceae are a family of Gram-negative bacteria. This family is a member of the order Enterobacterales in the class Gammaproteobacteria of the phylum Proteobacteria. Genera in this family include the type genus Hafnia, along with Edwardsiella and Obesumbacterium.
The Morganellaceae are a family of Gram-negative bacteria that include some important human pathogens formerly classified as Enterobacteriaceae. This family is a member of the order Enterobacterales in the class Gammaproteobacteria of the phylum Proteobacteria. Genera in this family include the type genus Morganella, along with Arsenophonus, Cosenzaea, Moellerella, Photorhabdus, Proteus, Providencia and Xenorhabdus.
Scandinavium is a genus of Gram-negative, facultative anaerobic, oxidase-negative, rod-shaped, motile bacteria of the family Enterobacteriaceae. It contains a single species, Scandinavium goeteborgense. The type strain of the species is S. goeteborgenseCCUG 66741T = CECT 9823T = NCTC 14286T and its genome sequence is publicly available in DNA Data Bank of Japan, European Nucleotide Archive and GenBank under the accession number LYLP00000000.
References
- ↑ Kosako, Y; Sakazaki, R; Yoshizaki, E (June 1984). "Yokenella regensburgei gen. nov., sp. nov.: a new genus and species in the family Enterobacteriaceae". Japanese Journal of Medical Science & Biology. 37 (3): 117–24. doi: 10.7883/yoken1952.37.117 . PMID 6503024.
- ↑ LPSN LSPN bacterio.net