Escherichia coli O157:H7 infections: Discordance between filterable fecal Shiga toxin
Escherichia coli O157:H7 infections: Discordance between filterable fecal Shiga toxin and disease outcome. Cornick NA, Jelacic S, Ciol MA, Tarr PI. The Journal of Infectious Diseases 2002;186:57-63.
Shiga toxin (Stx)-producing Escherichia coli O157:H7 are the most common cause of hemolytic uremic syndrome (HUS). Children less than 10 years of age in the U.S. Pacific Northwest region were studied to determine whether Stx was detectable and neutralizable by specific antibodies to Stx1 and Stx2. Filterable Stx was detected in the stools of 48% of children in the uncomplicated group and 40% in the pre-HUS group. Only one of six stools from children with HUS, which is often accompanied by diminished fecal output, had detectable filterable fecal Stx. The average number of days of illness was similar for the children with positive and negative filtrates. There was no significant correlation between the concentration of fecal E. coli O157H:7 and the titer of fecal Stx. In children’s stool samples obtained on or before day four of illness, each 10-fold decrease in titer was associated with an eight-fold increased odds of developing HUS. The fecal Stx type did not correlate with the Stx expressed by bacteria grown in vitro and was not related to bacterial titer in the samples studied. These data suggest that therapeutic and diagnostic strategies directed toward binding or identifying fecal Stx in the intestine may have limited success.