''Escherichia'' ( ) is a

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

Gram-negative Gram-negative bacteria are bacteria that, unlike gram-positive bacteria, do not retain the crystal violet stain used in the Gram staining method of bacterial differentiation. Their defining characteristic is that their cell envelope consists ...

, non-

spore In biology, a spore is a unit of sexual reproduction, sexual (in fungi) or asexual reproduction that may be adapted for biological dispersal, dispersal and for survival, often for extended periods of time, in unfavourable conditions. Spores fo ...

-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 (; : bacterium) are ubiquitous, mostly free-living organisms often consisting of one Cell (biology), biological cell. They constitute a large domain (biology), domain of Prokaryote, prokaryotic microorganisms. Typically a few micr ...

from the family

Enterobacteriaceae Enterobacteriaceae is a large family (biology), family of Gram-negative bacteria. It includes over 30 genera and more than 100 species. Its classification above the level of Family (taxonomy), family is still a subject of debate, but one class ...

. 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 Digestion, digestive system that leads from the mouth to the anus. The tract is the largest of the body's systems, after the cardiovascula ...

s of

warm-blooded Warm-blooded is a term referring to animal species whose bodies maintain a temperature higher than that of their environment. In particular, homeothermic species (including birds and mammals) maintain a stable body temperature by regulating ...

animals, ''Escherichia'' species provide a portion of the microbially derived

vitamin K Vitamin K is a family of structurally similar, fat-soluble vitamers found in foods and marketed as dietary supplements. The human body requires vitamin K for post-translational modification, post-synthesis modification of certain proteins ...

for their host. A number of the species of ''Escherichia'' are

pathogen In biology, a pathogen (, "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 Germ theory of d ...

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 Fami ...

, the discoverer of ''

Escherichia coli ''Escherichia coli'' ( )Wells, J. C. (2000) Longman Pronunciation Dictionary. Harlow ngland Pearson Education Ltd. is a gram-negative, facultative anaerobic, rod-shaped, coliform bacterium of the genus '' Escherichia'' that is commonly fo ...

''. ''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 (; : flagella) (Latin for 'whip' or 'scourge') is a hair-like appendage that protrudes from certain plant and animal sperm cells, from fungal spores ( zoospores), and from a wide range of microorganisms to provide motility. Many pr ...

, 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. Lysine contains an α-amino group (which is in the protonated form when the lysine is dissolved in water at physiological pH), an α-carboxylic acid group ( ...

or hydrolyze

arginine Arginine is the amino acid with the formula (H2N)(HN)CN(H)(CH2)3CH(NH2)CO2H. The molecule features a guanidinium, guanidino group appended to a standard amino acid framework. At physiological pH, the carboxylic acid is deprotonated (−CO2−) a ...

. Species include '' E. albertii'', '' E. fergusonii'', '' E. hermannii'', '' E. ruysiae'', '' E. marmotae'' and most notably, the

model organism A model organism 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 workings of other organisms. Mo ...

and clinically relevant ''

E. coli ''Escherichia coli'' ( )Wells, J. C. (2000) Longman Pronunciation Dictionary. Harlow ngland Pearson Education Ltd. is a gram-negative, facultative anaerobic, rod-shaped, coliform bacterium of the genus ''Escherichia'' that is commonly foun ...

''. Formerly, ''

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 pat ...

'' and

Pseudescherichia vulneris ''Pseudescherichia vulneris'' is a Gram-negative bacterial species. ''P. vulneris'' is a fermentative, oxidase-negative, motile rod, which holds characteristics of the family Enterobacteraceae. This bacterium can colonize in the respiratory tract ...

were also 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 g ...

, certain strains of some species, most notably the pathogenic serotypes of ''

'', are human pathogens, and are the most common cause of

urinary tract infection A urinary tract infection (UTI) is an infection that affects a part of the urinary tract. Lower urinary tract infections may involve the bladder (cystitis) or urethra (urethritis) while upper urinary tract infections affect the kidney (pyel ...

s, significant sources of gastrointestinal disease, ranging from simple

diarrhea Diarrhea (American English), also spelled diarrhoea or diarrhœa (British English), is the condition of having at least three loose, liquid, or watery bowel movements in a day. It often lasts for a few days and can result in dehydration d ...

dysentery Dysentery ( , ), 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 may include dehyd ...

-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, mutualistic, 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.

References

External links

Escherichia
genomes and related information a
PATRIC
a Bioinformatics Resource Center funded b
NIAID
{{Authority control Gut flora bacteria Gram-negative bacteria Pathogenic bacteria Bacteria genera

Pathogenesis

See also

References

External links