Importance of environmental transmission in cases of EHEC O157 causing hemolytic uremic syndrome.

A local outbreak of Shiga toxin (Stx)-producing enterohemorrhagic Escherichia coli (EHEC) O157:H7 causing severe hemolytic-uremic syndrome (HUS) was found to be caused by environmental transmission. Automated ribotyping and pulsed-field gel electrophoresis revealed that four stx2-positive EHEC isolates obtained from two unrelated children, one mother and one cow were identical. Results of an epidemiological investigation strongly suggest that both children were infected via a meadow strewn with manure containing EHEC-positive feces from the infected cow a few days prior to the onset of illness. The cow belonged to a cattle farm neighboring the meadow. This report highlights the risk of acquiring EHEC O157 through indirect contact with a farm environment.