''Escherichia'' () is a
genus
Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nom ...
of
Gram-negative
Gram-negative bacteria are bacteria that do not retain the crystal violet stain used in the Gram staining method of bacterial differentiation. They are characterized by their cell envelopes, which are composed of a thin peptidoglycan cell wa ...
, non-
spore
In biology, a spore is a unit of sexual or asexual reproduction that may be adapted for dispersal and for survival, often for extended periods of time, in unfavourable conditions. Spores form part of the life cycles of many plants, algae, ...
-forming,
facultatively anaerobic
A facultative anaerobic organism is an organism that makes ATP by aerobic respiration if oxygen is present, but is capable of switching to fermentation if oxygen is absent.
Some examples of facultatively anaerobic bacteria are ''Staphylococcus' ...
, rod-shaped
bacteria
Bacteria (; singular: bacterium) are ubiquitous, mostly free-living organisms often consisting of one biological cell. They constitute a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria were am ...
from the family
Enterobacteriaceae
Enterobacteriaceae is a large family of Gram-negative bacteria. It was first proposed by Rahn in 1936, and now includes over 30 genera and more than 100 species. Its classification above the level of family is still a subject of debate, but o ...
.
In those species which are inhabitants of the
gastrointestinal tract
The gastrointestinal tract (GI tract, digestive tract, alimentary canal) is the tract or passageway of the digestive system that leads from the mouth to the anus. The GI tract contains all the major organs of the digestive system, in humans and ...
s of
warm-blooded
Warm-blooded is an informal term referring to animal species which can maintain a body temperature higher than their environment. In particular, homeothermic species maintain a stable body temperature by regulating metabolic processes. The on ...
animals, ''Escherichia'' species provide a portion of the microbially derived
vitamin K
Vitamin K refers to structurally similar, fat-soluble vitamers found in foods and marketed as dietary supplements. The human body requires vitamin K for post-synthesis modification of certain proteins that are required for blood coagulation ...
for their host. A number of the species of ''Escherichia'' are
pathogen
In biology, a pathogen ( el, πάθος, "suffering", "passion" and , "producer of") in the oldest and broadest sense, is any organism or agent that can produce disease. A pathogen may also be referred to as an infectious agent, or simply a g ...
ic. The genus is named after
Theodor Escherich
Theodor Escherich (; 29 November 1857 – 15 February 1911) was a German- Austrian pediatrician and a professor at universities in Graz and Vienna. He discovered and described the bacterium ''Escherichia coli''.
Life and achievements
Fam ...
, the discoverer of ''
Escherichia coli
''Escherichia coli'' (),Wells, J. C. (2000) Longman Pronunciation Dictionary. Harlow ngland Pearson Education Ltd. also known as ''E. coli'' (), is a Gram-negative, facultative anaerobic, rod-shaped, coliform bacterium of the genus '' Esc ...
''. ''Escherichia'' are facultative aerobes, with both aerobic and anaerobic growth, and an optimum temperature of 37 °C.
''Escherichia'' are usually motile by
flagella
A flagellum (; ) is a hairlike appendage that protrudes from certain plant and animal sperm cells, and from a wide range of microorganisms to provide motility. Many protists with flagella are termed as flagellates.
A microorganism may have fro ...
, produce gas from fermentable carbohydrates, and do not decarboxylate
lysine
Lysine (symbol Lys or K) is an α-amino acid that is a precursor to many proteins. It contains an α-amino group (which is in the protonated form under biological conditions), an α-carboxylic acid group (which is in the deprotonated − ...
or hydrolyze
arginine
Arginine is the amino acid with the formula (H2N)(HN)CN(H)(CH2)3CH(NH2)CO2H. The molecule features a guanidino group appended to a standard amino acid framework. At physiological pH, the carboxylic acid is deprotonated (−CO2−) and both the am ...
.
Species include ''
E. albertii'', ''
E. fergusonii'', ''
E. hermannii'', ''
E. marmotae'' and most notably, the
model organism
A model organism (often shortened to model) is a non-human species that is extensively studied to understand particular biological phenomena, with the expectation that discoveries made in the model organism will provide insight into the workin ...
and clinically relevant ''
E. coli''. ''
Shimwellia blattae
''Shimwellia blattae'' (formerly ''Escherichia blattae'') is a species of bacterium, one of two in the genus '' Shimwellia''. It is an aerobic enteric bacterium first isolated from the hindgut of cockroaches. Although it is related to human path ...
'' was formerly classified in this genus.
Pathogenesis
While many ''Escherichia'' are commensal members of the
gut microbiota
Gut microbiota, gut microbiome, or gut flora, are the microorganisms, including bacteria, archaea, fungi, and viruses that live in the digestive tracts of animals. The gastrointestinal metagenome is the aggregate of all the genomes of the gut mi ...
, certain strains of some species, most notably the
pathogenic serotypes of ''
E. coli'', are human pathogens,
and are the most common cause of
urinary tract infection
A urinary tract infection (UTI) is an infection that affects part of the urinary tract. When it affects the lower urinary tract it is known as a bladder infection (cystitis) and when it affects the upper urinary tract it is known as a kidne ...
s,
significant sources of gastrointestinal disease, ranging from simple
diarrhea
Diarrhea, also spelled diarrhoea, is the condition of having at least three loose, liquid, or watery bowel movements each day. It often lasts for a few days and can result in dehydration due to fluid loss. Signs of dehydration often begin w ...
to
dysentery
Dysentery (UK pronunciation: , US: ), historically known as the bloody flux, is a type of gastroenteritis that results in bloody diarrhea. Other symptoms may include fever, abdominal pain, and a feeling of incomplete defecation. Complications ...
-like conditions,
as well as a wide range of other pathogenic states
classifiable in general as colonic escherichiosis. While ''E. coli'' is responsible for the vast majority of ''Escherichia''-related pathogenesis, other members of the genus have also been implicated in human disease.
''Escherichia'' are associated with the imbalance of
microbiota
Microbiota are the range of microorganisms that may be commensal, symbiotic, or pathogenic found in and on all multicellular organisms, including plants. Microbiota include bacteria, archaea, protists, fungi, and viruses, and have been found ...
of the lower reproductive tract of women. These species are associated with inflammation.
See also
*
''E. coli'' O157:H7
*
List of bacterial genera named after personal names
References
External links
Escherichiagenomes and related information a
PATRIC a Bioinformatics Resource Center funded b
NIAID
{{Taxonbar, from=Q311055
Gut flora bacteria
Gram-negative bacteria
Pathogenic bacteria
Bacteria genera