Microbiology and Immunology

Escherichia coli WORLD OF MICROBIOLOGY AND IMMUNOLOGY

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The bacterium, particularly one type called strain K–12,

is one of the most widely studied organisms in modern

research. Its biochemical behavior and structure are well

known, having been studied for much of this century. This

plethora of information has made E. coliindispensable as the

bacterial model system for biochemical, behavioral and struc-

tural studies. E. coliis also the most encountered bacterium in

clinical laboratories, being the primary cause of human uri-

nary tract infections. Pathogenic (diseases causing) strains of

E. coliare responsible for pneumonia, meningitisand trav-

eler’s diarrhea.

As part of the normal flora of the intestinal tract, E. coli

is beneficial. It is crucial in the digestion of food, and is our

principle source of vitamin K and B-complex vitamins.

Scanning electron micrograph of an Escherichia colibacterium.

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