E Coli

e coli Description

E Coli - Escherichia coli (usually abbreviated to E. coli) is one of the main species of bacteria that live in the lower intestines of warm-blooded animals (including birds and mammals) and are necessary for the proper digestion of food. Its presence in groundwater is a common indicator of fecal contamination. ("Enteric" is the adjective that describes organisms that live in the intestines. "Fecal" is the adjective for organisms that live in feces, so it is often a synonym for "enteric.") The name comes from its discoverer, Theodor Escherich. It belongs among the Enterobacteriaceae, and is commonly used as a model organism for bacteria in general.

The number of individual E. coli bacteria in the feces that one human passes in one day averages between 100 billion and 10 trillion. All the different kinds of fecal coli bacteria and all the very similar bacteria that live in the ground (in soil or decaying plants, of which the most common is Enterobacter aerogenes) are grouped together under the name "coliform" (meaning "like coli") bacteria. Technically, the "coliform group" is defined to be all the aerobic and facultative anaerobic, non-spore-forming, Gram-negative, rod-shaped bacteria that ferment lactose with the production of gas within 48 hours at 35°C (95°F) (in the body, this gas is released as flatulence).
 
 
Role in water purification and sewage treatment
In the fields of water purification and sewage treatment, E. coli was chosen very early in the development of the technology as an "indicator" of the pollution level of water, meaning the amount of human fecal matter in it, measured using the Coliform Index. The main reasons for using E. coli are that there are a lot more coliforms in human feces than there are pathogens (such as Salmonella typhi, which causes typhoid), and E. coli is usually harmless, so it can't "get loose" in the lab and hurt anyone. It can be misleading to use E. coli as an indicator of human fecal contamination because there are other environments in which E. coli grows well, such as paper mills.

Role in disease
There are, however, three situations where the otherwise harmless E. coli can cause illness: