Escherichia coli

Rod-shaped Gram-negative bacterium (see bacteria) that lives, usually harmlessly, in the colon of most warm-blooded animals. It is the commonest cause of urinary tract infections in humans. It is sometimes found in water or meat where faecal contamination has occurred and can cause severe gastric problems.

The mapping of the genome of E. coli, consisting of 4,403 genes, was completed in 1997. It is probably the organism about which most molecular genetics is known, and is of pre-eminent importance in recombinant DNA research.

Classification

In April 1997, the US Centers for Disease Control and Prevention estimated that the commonest toxic Escherichia coli strain, 0157:H7, may be responsible for illness in at least 20,000 people in the USA each year.