Hemolytic uremic syndrome: co-infection with two different serotypes of Shiga-like toxin producing Escherichia coli.

We report a case of a child who developed Hemolytic Uremic Syndrome in whom two Shiga-like toxin (SLT)-producing Escherichia coli strains of different serotypes and genotypes, were simultaneously isolated from stools. In addition, one of these strains represented a new toxin producing serotype. Strain 1 belonged to serotype O157: H7, biotype D, produced SLT II and was susceptible to all antibiotics tested. This strain hybridized with gene probes for SLT II, fimbrial adhesion (EHEC factor) and attaching and effacing factor (eae). Strain 2 belonged to serotype 025: K2: H2, produced SLT II and had a multiresistant antibiotic susceptibility pattern. This strain hybridized with the EHEC gene probe but not with SLT I, SLT II and eae gene probes. Free fecal SLT II cytotoxin was detected in stools of the child and his father, suggesting that the infection may have been acquired from a household contact.