Escherichia coli O157:H7.

E. coli O157:H7 can cause potentially lethal illness in hosts of all ages. These patients often are evaluated and treated by gastroenterologists. The treating physician should administer adequate hydration, usually parenterally, and avoid the use of antibiotics and antimotility agents. The physician needs to notify immediately the appropriate public health authorities of the diagnosis and to ensure that the isolate is recovered by the microbiologist and forwarded for molecular linkage analyses.