The Well Known Microbe: E. coli

Kingdom: Eubacterium Scientific Name: Escherichia coli Image Courtesy of: Shirley Owens, Center for Electron Optics, MSU Image Width: 9.5 microns Image Technology: SEM (Scanning Electron Microscope) Click here to see a big picture of this microbe.

E. coli is the lab rat of the bacterial world. More details are known about the molecular biology of this organism that any other, including humans. E. coli is very popular for use in research because it is so easy to grow, with a fast doubling time of only 20 minutes.

E. coli was discovered in 1885 by Theodor Escherich, a German bacteriologist. E. coli is used in industrial biotechnology to produce enzymes.

E. coli is a normal resident of the large intestine in healthy people. It is a type of probiotic organism because it crowds out disease causing bacteria. E. coli also makes vitamin K which humans require to be healthy.

Although it is generally a good microbe, some strains make people sick. The toxic strains of this microbe are responsible for about half of all cases of traveler's diarrhea. One famous strain, O157:H7, has caused disease in people who eat uncooked hamburger.

E. coli was the first bacterium to have been observed mating (conjugation in bacteria). Conjugations is transferring DNA from one cell to another cell.

Glossary

scanning electron microscope - an electron microscope that bounces electron off a sample to create a 3-D image.

 © 1999 Comm Tech Lab, Michigan State University. This work was created with support from the National Science Foundation and the Center for Microbial Ecology at Michigan State University. Current maintenance is supported by the International Society for Microbial Ecology and the Comm Tech Lab. The Microbe of the Month is sponsored by the International Society for Microbial Ecology.