E
.coli is a bacterium that is
commonly found in the gut of
humans and other warm-blooded
animals. It is one of the most
frequent causes of many common
bacterial infections, including
cholecystitis, bacteremia,
cholangitis, urinary tract
infection, and traveller’s
diarrhoea, and other
clinical infections such as
neonatal meningitis and
pneumonia.
The genus Escherichia is named after
Theodor Escherich, who isolated the type
species of the genus. E. coli is a small,
catalase-positive, oxidase-negative, gramnegative bacillus in the. family
Enterobacteriaceae.
It characteristically reduces nitrates,
ferments glucose and usually lactose, and is
either motile (with peritrichate flagella) or
non-motile.
There are many types of E. coli, and most
of them are harmless. But some can cause
bloody diarrhea. These are called enterohemorrhagic E. coli (EHEC). One common
type is called E. coli O157:H7. In some
people, this type of E. coli may also cause
severe anaemia or kidney failure, which can
lead to death. Other strains of E. coli can
cause urinary tract infections or other
infections.
The pathogenesis of
enteric E. coli infections
begins with the ingestion
of the organism in
contaminated food or water,
which then faces the normal gastric acid
barrier.