  Escherichia coli 0157:H7 doesn't need a publicist. It's had more than its share of press coverage during the last few years, and deservedly so. Not only does E. coli 0157:H7 produce a standard gastrointestinal food-borne illness characterized by diarrhea and stomach cramps, but it also produces a toxin that can cause kidney failure in the young and old. A Seattle pediatrician noticed a larger than normal number of children with hemolytic uremic syndrome, the most common cause of kidney failure in children. All of these cases were traced to 0157:H7, and essentially all of the 0157:H7 was traced to contaminated beef or unpasteurized milk. Unfortunately, by the time the children came to him, the pediatrician couldn't do much but maintain them and wait out the disease. The kidney symptoms don't show until about a week after the 0157:H7 infection, when a large amount of toxin had already been produced. Prevention of future E. coli 0157:H7 outbreaks is the best way to deal with this food-borne bacteria. Prevention requires knowing where the bacteria that contaminated the beef and milk originated. As part of the normal stomach and intestinal flora of cattle, E. coli 0157:H7 ends up in the cattle's feces. During slaughter some of the bacteria contaminates the surface of the carcass. These surfaces are often trimmed from the carcass and added to other trims to be ground into hamburger. Current efforts to reduce the contamination involve the development of surface treatments that can be used in slaughterhouses. Meanwhile, the consumer can counteract contamination by cooking ground beef thoroughly. Until the primary sources of 0157:H7 that infect cattle are found, it will be difficult to develop methods to prevent infection. Although 0157:H7 infections happen sporadically in almost all cattle herds on almost all farms, the occurrence of most during warm weather suggests an environmental factor in the transmission. Infections last for about one or two months, then are gone. E. coli 0157:H7 does not cause disease in the animals. It is known that 0157:H7 can multiply enthusiastically in moist cattle feeds and that it's found in water troughs on many farms, where it can persist for long periods of time. WSU veterinary epidemiologist Tom Besser has some in his lab that have lived for two years in distilled water. As he says, "This is one sturdy bacteria." —Mary Aegerter |