E. coli: Friend AND Foe Escherichia coli is a species of bacterium commonly found in the gastro-intestinal tract of warm-blood animals including humans. These organisms partake in a symbiotic relationship with us, absorbing nutrients and living within the confines of the gut. In turn, these bacteria provide us with some essential nutrients and protect us from infection. Some strains of E. coli may invade bodily tissue and cause infection. The consumption of spoilt food-products is often the cause.

Under the Microscope… These organisms have several peculiar features: They are rod-shaped overall. They contain finger-like pili structures (‘P’) to sense their surrounding environment. They possess flagella (‘F’) which act as ‘propellers’ to afford motility.

In the Lab… E. coli has both industrial and research applications due to its ease of growth and manipulation. Through the use of recombinant DNA technology, E. coli cells are used to produce human insulin, vaccines, antibiotics and other important pharmaceuticals in industry. In research, E. coli serves as a model organism in studies of pathogens such as Salmonella spp. due to physiological similarities.