The
Enterobacteriaceae are a large
family of
Gram-negative bacteria that includes, along with many harmless
symbionts, many of the more familiar
pathogens, such as
Salmonella,
Escherichia coli,
Yersinia pestis,
Klebsiella and
Shigella. Other disease-causing bacteria in this family include
Proteus,
Enterobacter,
Serratia, and
Citrobacter. This family is the only representative in the order Enterobacteriales of the class
Gammaproteobacteria in the phylum
Proteobacteria. Phylogenetically, in the Enterobacteriales, several
peptidoglycan-less insect endosymbionts form a
sister clade to the Enterobacteriaceae, but as they are not
validly described, this group is not officially a taxon; examples of these species are
Sodalis,
Buchnera,
Wigglesworthia,
Baumannia cicadellinicola and
Blochmannia, but not former
Rickettsias. Members of the Enterobacteriaceae can be trivially referred to as enterobacteria or "enteric bacteria", as 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 after the
genus Enterobacter (which would be "Enterobacteraceae")— and the type genus is
Escherichia.
