Escherichia coli

Bacteria Shape

Escherichia coli is a bacillus shaped bacterium that does not form colonies.

Gram Stain

Escherichia coli is a gram negative bacterium. Gram negative means that it has a two layer cell wall composed of a thin, inner layer of peptidoglycan and an outer membrane of phospholipids, lipopolysaccharide, and lipoprotein.

Environmental Effects

Escherichia coli grows the best on nutrient agar dishes at 37 degrees Celsius. It produces an acid waste. E. col is motile. Motility was tested in a tube of MIO agar and examined for growth along just the stab line or if it was everywhere. E. coli has has gamma hemolysis meaning that it does not digest hemoglobin. This was tested b growing the bacteria on sheep's blood agar plates. E. coli is Aerobic meaning that it cannot grow withuot oxygen. This was tested by putting an inoculated plate into a pickle jar and then putting a candle in to take up all the oxygen.


A Bauer-Kirby test was performed, antibiotics that killed E. coli were Tetracycline, Chloramphenicol, and Vancomycin. Tetracycline and Chloramphenicol interfere with protein synthesis. Vancomycin interferes with cell wall synthesis.

The Good(MOI)

Escherichia coli is commonly found in the lower intestine of endothermic organisms. Most E. coli types are harmless, in fact they often help their hosts digest food. They even prevent the establishment of harmful bacteria in the intestine.

The Bad

Escherichia coli can cause serious sickness in humans, and are occasionally responsible for major product recalls.These harmful strains are contracted by coming into contact with fecal matter from an animal carrying the bacteria. The exposure often comes from eating vegetables that have been fertilized with cow manure that was not composted long enough.

The Ugly

When E. coli goes on the warpath things get nasty. Symptoms include:
                      • Severe stomach cramps and stomach tenderness.
                      • Diarrhea watery at first, but often becoming very bloody.
                      • Nasuea and vomiting

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