enterobacterium

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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.

Characteristics

Members of the Enterobacteriaceae are rod-shaped, and are typically 1-5 μm in length. Like other Proteobacteria they have Gram-negative stains,^[1] and they are facultative anaerobes, fermenting sugars to produce lactic acid and various other end products. Most also reduce nitrate to nitrite, although exceptions exist (e.g. Photorhabdus). Unlike most similar bacteria, Enterobacteriaceae generally lack cytochrome C oxidase, although there are exceptions (e.g. Plesiomonas shigelloides). Most have many flagella used to move about, but a few genera are non-motile. They are non-spore forming. Catalase reactions vary among Enterobacteriaceae.

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.

Most members of Enterobacteriaceae have peritrichous Type I fimbriae involved in the adhesion of the bacterial cells to their hosts.

Examples/classification

Genera

• Alishewanella
• Alterococcus
• Aquamonas
• Aranicola
• Arsenophonus
• Azotivirga
• Blochmannia
• Brenneria
• Buchnera
• Budvicia
• Buttiauxella
• Cedecea
• Citrobacter
• Cronobacter
• Dickeya
• Edwardsiella
• Enterobacter
• Erwinia, e.g. Erwinia amylovora
• Escherichia, e.g. Escherichia coli
• Ewingella
• Grimontella
• Hafnia
• Klebsiella, e.g. Klebsiella pneumoniae
• Kluyvera
• Leclercia
• Leminorella
• Moellerella
• Morganella
• Obesumbacterium
• Pantoea
• Pectobacterium see Erwinia
• Candidatus Phlomobacter
• Photorhabdus, e.g. Photorhabdus luminescens
• Plesiomonas, e.g. Plesiomonas shigelloides
• Pragia
• Proteus, e.g. Proteus vulgaris
• Providencia
• Rahnella
• Raoultella
• Salmonella
• Samsonia
• Serratia, e.g. Serratia marcescens
• Shigella
• Sodalis
• Tatumella
• Trabulsiella
• Wigglesworthia
• Xenorhabdus
• Yersinia, e.g. Yersinia pestis
• Yokenella

References

External links

• Genome information on diarrheagenic E. coli, Shigella, Salmonella, Yersinia pestis, and Yersinia enterocolitica is available at the NIAID Enteropathogen Resource Integration Center (ERIC)

• Evaluation of new computer-enhanced identification program for microorganisms: adaptation of BioBASE for identification of members of the family Enterobacteriaceae [1]

References

MacFaddin, Jean F. Biochemical Tests for Identification of Medical Bacteria. Williams & Wilkins, 1980, p 441.