Escherichia coli & Shigella



Both Escherichia coli (E. coli) and Shigella spp. produce a potent shigatoxin during infection that causes severe and life-threatening disease. These species are very closely related and have some similarity in their symptomology, but E. coli infections are a particularly serious problem in children. Symptoms include fever and bloody diarrhea. Even with treatment symptoms can progress to hemolytic uremic syndrome, which damages the kidney and leads to multiple organ failure, including brain damage. E. coli symptoms in adults are usually much milder and produce more typical gastrointestinal problems. Shigella, however, may produce serious bloody diarrhea both adults and children.


Treatment may be complicated by the severity of the disease and by the fact that killing the bacteria can release more toxin. No vaccine is available for humans.


The initial outbreak of E. coli in the US involved children that had eaten undercooked hamburgers at a fast food chain. More stringent requirements for cooking temperatures have reduced the risks. However, recent outbreaks have involved other meats, as well a various produce (bean sprouts, raspberries, lettuce) that is generally eaten raw. Frequently, these products have been imported from other countries where hygiene standards may be lower than those in the US. A recent E. coli outbreak at a fair in Florida highlighted some of the problems with E. coli disease. Apparently, limited contact with infected calves at a petting zoo produced disease in several children. The infectious dose appears to be very low for children, and any close contact with animals, particularly cattle that may be carriers, should be avoided.


CHILDREN SHOULD NOT EAT UNDERCOOKED MEATS. Hamburgers should be cooked well done with no pink. Washing hands and food products will reduce risk. Avoiding exposure to uncooked food of any kind may be advisable for small children. Children that lack toilet training should not participate in enclosed swimming activities because they present an opportunity for fecal contamination and spread of E. coli disease.

Prepared by Anita C. Wright, Ph.D.
Associate Professor of Food Microbiology
University of Florida Food Science and Human Nutrition Department

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