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(taxonomy) A genus belonging to the family Enterobacteriaceae, which includes species that are gram-negative, rod-shaped, non-spore-forming, and occurring in the lower part of the intestine of humans and other mammals


Escherichia is a genus of the family Enterobacteriaceae. A very well-known species is the Escherichia coli (E. coli). Members of this genus are commonly found as a normal flora in the lower intestine of humans and other warm-blooded animals. Most of them are nonpathogenic. Normal gut flora E. coli are beneficial to their host, particularly in the production of vitamin K2.1 There are strains though that are pathogenic or opportunists. Virulent strains of E. coli have been associated with gastroenteritis, urinary tract infections, and neonatal meningitis. E. coli #0157:H7 strain, for instance, can produce Shiga toxin that is capable of causing premature destruction of erythrocytes. The destroyed erythrocytes may clog the kidneys and cause hemolytic-uremic syndrome, which in turn is risky since it can lead to stroke and other complications in the lungs and heart.

Word origin: named after Theodor Escherich, a German pediatrician, that first to describe the species Escherichia coli

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1 Bentley, R. & Meganathan, R. (1982). "Biosynthesis of vitamin K (menaquinone) in bacteria". Microbiol. Rev. 46 (3): 241–80.