E coli bacteria. Picture taken from a public domain

Classification Information

Domain: Bacteria

Kingdom: Bacteria

Phylum: Proteobacteria

Class: Gammaproteobacteria

Order: Enterobacteriales

Family: Enterobacteriaceae

Genus: Escherichia

Species: Escherichia coli O157:H7 (E. coli O157:H7)

Why that Classification?

Domain/Kingdom of Bacteria: E. Coli O157:H7 fits here because it is prokaryotic (meaning it has no nucleus, or membrane bound organelles), and unicellular.

Phylum of Proteobacteria: The major characteristic that classifies E. coli O157:H7 is Gram negative meaning its outer membrane contains mostly lipopolysaccharides.Phylogetic tree of phylums. Drawn by author with information from EMLab.

Class of Gammaproteobacteria: E. coli o157:H7 fits here because it is an anaerobic and fermentation gram negative bacteria.

Order of Enterobacteriales: E. coli O157 fits here because it is rod-shaped.

Family of Enterobacteriaceae: E. coli O157 is put into this category because it can be an animal parasite.

Genus of Escherichia: E. coli O157 is placed in this genus because it is mostly found in the human intestine but also present in soil and water.

Photo showing how distantly related strains are. Photo drawn by author with information from openi beta.

Species of Escherichia coli O157: This is one of the species that fall under the genus above. Throughout the site we will talk more about what makes this species unique. This strain was named this way because it is somatic giving it O it is the antigen 157 and finally it has a flagella giving it the H with antigen 7. you combine all of these and you get the strand O157:H7. You can see how distantly related the different strains of E. coli differ in the picture to the left.

Want to learn about more bacteria? Click on the following links to learn more!

Xanthomonas campestris
Streptococcus pyogenes
Bordetella pertussis
Clostridium difficile

Let us continue learning about E. coli O157 by learning about its Habitat.