Escherichia coli
Escherichia coli
Scientific classification
Phylum: Proteobacteria
Class:
Gamma Proteobacteria
Order:
Enterobacteriales
Family:
Enterobacteriaceae
Genus:
Escherichia
Species: E. coli
Binomial name
Escherichia coli
(Migula 1895)
Castellani and Chalmers 1919
Escherichia coli (commonly E. coli; pro-
nounced /ˌɛʃɪˈrɪkiə ˈkoʊlaɪ/, /iː ~/, and named
for its discoverer), is a Gram negative bac-
terium that is commonly found in the lower
intestine of warm-blooded organisms (endo-
therms). Most E. coli strains are harmless,
but some, such as serotype O157:H7, can
cause serious food poisoning in humans, and
are occasionally
responsible
for
costly
product recalls.[1][2] The harmless strains are
part of the normal flora of the gut, and can
benefit their hosts by producing vitamin
K2,[3] or by preventing the establishment of
pathogenic bacteria within the intestine.[4][5]
E. coli are not always confined to the in-
testine, and their ability to survive for brief
periods outside the body makes them an
ideal
indicator
organism
to
test
environmental samples for fecal contamina-
tion.[6][7] The bacteria can also be grown eas-
ily and its genetics are comparatively simple
and easily-manipulated or duplicated through
a process of metagenics, making it one of the
best-studied prokaryotic model organisms,
and an important species in biotechnology
and microbiology.
E. coli was discovered by German pediatri-
cian and bacteriologist Theodor Escherich in
1885,[6] and is now classified as part of the
Enterobacteriaceae family of gamma-proteo-
bacteria.[8]
Strains
Model of successive binary fission in E. coli
A strain of E. coli is a sub-group within the
species that has unique characteristics that
distinguish it from other E. coli strains. These
differences are often detectable only on the
molecular level; however, they may result in
changes to the physiology or lifecycle of the
bacterium. For example, a strain may gain
pathogenic capacity, the ability to use a
unique carbon source, the ability to inhabit a
particular ecolo