E. Coli, the Most Popular Bacterium

Posted January 29th, 2013

E. Coli.  You Hear About It In the News, but Do You Really Know What It Is?

Escherichia coli,  usually known simply as E. coli, was named after its discoverer Theodor Escherich,  a German doctor in the 19th century. It is part of a family of fecal bacteria called coliform.  It is found in the intestines of animals and humans and will grow in a wide range of intestinal environments.  A typical E. coli measures about 2 microns by 0.5 microns and is rod shaped.

When water tests are done, a test is usually first performed for coliform, and if coliform is detected, E. coli, specifically, is looked for.  Water can test positive for coliform bacteria without E. coli being present. Although finding E. coli is an immediate cause for concern, most strains of E. coli are harmless.  A few strains, like O157:H7, O121 and O104:H21, cause serious disease.

Rod-shaped E. coli  are often about 2 microns long and half a micron across. This makes them big enough to be caught by a tight water filter.

E. coli can infect humans not only through contaminated water but also through foods like insufficiently cooked beef, contaminated, unwashed fresh vegetables, as well as milk or juice.

Presence of E. coli in water is a strong indication that water is contaminated by human or animal feces.

Health effects of E. coli range from no symptoms to death, although in most cases infected individuals recover without medical treatment.  Serious outbreaks, though not frequent in this country, are  impressive.   In 1999 at a county fair in New York, a well at the fair used for drinking and food preparation was contaminated by manure from a nearby animal barn. The result was two deaths, 65 people hospitalized and more than 1,000 sickened.

The EPA considers detection of E. coli a “direct health risk,” and has set an MCL for total coliforms of zero.

Treatment of E. coli is varied.  It includes  ultrafiltration, nanofiltration, reverse osmosis, distillation, ultraviolet, chlorination, ozone, boiling.

Reference: Water Technology.

More Information:  Pure Water Products.