Escherichia coli (E. coli) are rod-shaped bacteria with fine hair-like appendages called ‘flagella’ that make it appear like a many-legged spider. It is a member of the Enterobacteriaceae family, which also includes Salmonella, Yersinia, and Shigella. All attack the digestive tract and are excreted in the feces. Disease is caused by the action of the circulating toxin more so than as a direct result of the bacteria. Travellers to another area of the world often end up with a form of E. coli infection, whether obtained from undercooked meat, raw milk, or even from swimming in a pool.
E. coli is part of the natural intestinal flora of humans and animals. It comes in many different strains, and is capable of reproducing at an astronomical rate. With the right conditions, one E.coli cell could multiply into a mass greater than the earth in three days. Usually though, they just simply double their population every two hours. Most strains are harmless, but there are five strains that produce toxins that cause diarrhea of varying levels of severity. One strain, E.coli 0157:H7 (Escherichia coli Hemorrhagic Colitis 0157:H7) causes acute hemolytic anemia and renal failure. Worse yet, it is resistant to many antibiotics – and for a long time now. By 1959, it was already apparent that Shigella dysenteriae was resistant to four classes of antibiotics – tetracycline, sulphonamide, streptomycin, and chloramphenicol. About the same time, Japanese scientists discovered that E.coli had an identical range of resistance.
E. coli is showing a particular danger to premature infants, apparently caused by antibiotics. The rate of group B streptococcus blood infections of newborns fell by nearly 75% during the 1990s, but, at the same time, E. coli infections more than doubled. It is speculated that such antibiotics as ampicillin were given to the pregnant women in labor to keep from passing the strep bacteria on to their newborns. As a consequence, E. coli flourished.
E. coli 0157:H is a mutation discovered in 1982 that has at least 62 subtypes to date. The toxin that is developed and released is not yet completely understood; but, since the bacteria live as part of the natural flora in cattle, it is thought that its pathogenic behavior has come about as a result of overuse of antibiotics in livestock. It is particularly destructive in children; but, in extreme cases, an adult can develop a bleeding disorder called TTP (thrombotic thrombocytopenic purpura) in which the blood no longer clots and begins to ooze through the mouth. Obviously, the prognosis at this point is not good.
