Enterobacteriaceae

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?Enterobacteria

Scientific classification

Kingdom:	Bacteria
Phylum:	Proteobacteria
Class:	Gamma Proteobacteria
Order:	Enterobacteriales
Family:	Enterobacteriaceae Rahn, 1937

Genera

See text.

The Enterobacteriaceae are a large family of bacteria, including many of the more familiar pathogens, such as Salmonella and Escherichia coli. Genetic studies place them among the Proteobacteria, and they are given their own order (Enterobacteriales), though this is sometimes taken to include some related environmental samples.

Members of the Enterobacteriaceae are rod-shaped, and are typically 1-5 μm in length. Like other Proteobacteria they have Gram-negative stains, and they are facultative anaerobes, fermenting sugars to produce lactic acid and various other end products. They also reduce nitrate to nitrite. Unlike most similar bacteria, Enterobacteriaceae generally lack oxidase, although there are exceptions (e.g. Plesiomonas). Most have many flagella used to move about, but a few genera are non-motile. They are non-spore forming and catalase-positive except for Shigella dysenteriae strains.

Many members of this family are a normal part of the gut flora found in the intestines of humans and other animals, while others are found in water or soil, or are parasites on a variety of different animals and plants. Escherichia coli, better known as E. coli, is one of the most important model organisms and its genetics and biochemistry have been closely studied.