The family enterobacteriaceae

Abstract

Enterobacteriaceae is a family of Gram-negative, facultatively anaerobic, non-spore-forming rods. Characteristics of this family include being motile, catalase positive, and oxidase negative; reduction of nitrate to nitrite; and acid production from glucose fermentation. However, there are also many exceptions. Currently, the family comprises 51 genera and 238 species. The number of species per genus ranges from 1 to 22. Twenty-two genera contain only one species, while seven genera have more than ten species. Enterobacteriaceae is closest to Vibrionaceae and Pasteurellaceae as sister clades with all members except for the genera Arsenophonus and Thorsellia being clustered together in one clade. Of the 30 genera with two or more species, 21 are likely to be monophyletic based on clustering on 16 rDNA sequence and other data. However, seven genera are likely to be polyphyletic requiring further reclassification. Enterobacteriaceae has been heavily sequenced from across the spectrum of the family diversity with 180 complete genomes covering 47 species and 21 genera. The genome size ranges from 422,434 bp, coding for just 362 ORFs, to 6,450,897 bp, coding for 5,909 ORFs. Enterobacteriaceae is ubiquitous in nature. Many species can exist as free living in diverse ecological niches, both terrestrial and aquatic environments, and some are associated with animals, plants, or insects only. Many are significant human, other animal, and/or plant pathogens causing a range of infections. There are numerous applications using members of Enterobacteriaceae including biocontrol in agriculture, production of numerous recombinant proteins and nonprotein products, control of infection diseases, anticancer agents, biowaste recycling, and bioremediation. Genome-based phylogeny and genomics are expected to further delineate the members of Enterobacteriaceae and refine the classification of the genera and species within this family.