Determination by DNA hybridization of Shiga-like-toxin-producing Escherichia coli in children with diarrhea in Thailand

Specific DNA probes were used to identify Shiga-like-toxin (SLT) I- and II-producing Escherichia coli from children less than 5 years of age with bloody diarrhea, in infants with diarrhea, and in controls of the same age without diarrhea in Thailand. At one hospital, SLT-producing E. coli was identified in 4 (7%) of 54 children with bloody diarrhea from whom other enteric pathogens were not identified and from 3 (6%) of 50 children without diarrhea. In the positive specimens, SLT-producing E. coli constituted only 0.3 to 4% of the 100 to 300 colonies on the replica blots. Non-toxin-encoding 933J and 933W bacteriophagelike DNA sequences were detected by colony hybridization with E. coli isolates from 18 (33%) of 54 children with bloody diarrhea and 23 (46%) of 50 controls. At another hospital, SLT-producing E. coli was not identified in 115 infants with diarrhea and 119 controls without diarrhea. One infant with diarrhea was infected with E. coli O76:H7 that hybridized with the enterohemorrhagic E. coli probe but not with the SLT probes. E. coli producing SLT I or SLT II was isolated in small numbers from a similar proportion of Thai children with bloody diarrhea in whom no other enteric pathogen was identified and from controls without diarrhea.