E. coli

In the 1880s, outbreaks of infant diarrhea raged through European cities and killed hundreds of babies. Like other physicians, Austrian pediatrician Theodore von Escherich struggled to save his patients and simultaneously find the infection’s cause. He recovered various bacteria from stool samples without an idea as to their role, if any, in the illness. In 1885 von Escherich published a medical article describing 19 bacteria that dominated the infants’ digestive tracts. One in particular seemed to be consistently present and in high numbers. He named it (with a striking lack of creativity) Bacterium coli commune for “common colon bacterium.” In 1958, the microbe was renamed Escherichia coli in honor of its discoverer.

E. coli’s physiology offers nothing remarkable. It does not pump out an excess of useful or unique enzymes or make antibiotics. It dominates the newborn’s intestinal tract but gradually other bacteria overtake it and carry out the important microbial reactions of digestion. For example, strict anaerobes produce copious amounts of digestive enzymes that help break down proteins, fats, and carbohydrates. These bacteria also partially digest fibers and synthesize proteins and vitamins that are used in the host’s metabolism. E. coli does not contribute as much to digestive activities as the strict anaerobes, but because it is a facultative anaerobe that uses oxygen when present and lives without oxygen in anaerobic places, its main role is to deplete oxygen so that anaerobic bacteria can flourish.