Sorbitol-fermenting Shiga toxin-producing Escherichia coli O157: indications for an animal reservoir

This study investigates a sorbitol-fermenting enterohaemorrhagic Escherichia coli (SF EHEC) O157 infection in a farmer's family in the Austrian province of Salzburg. The investigation commenced after a 10-month-old boy was admitted to hospital with the clinical diagnosis of a haemolytic-uraemic syndrome (HUS) and his stool specimen grew SF EHEC O157:H-. In a subsequent environmental survey, a stool specimen of the 2-year-old brother and faecal samples of two cattle from the family's farm were also found to be positive for SF EHEC O157:H-. All four isolates had indistinguishable phenotypic and molecular characteristics and were identical to the first strain detected in Bavaria in 1988. Despite identical isolates being demonstrated in Bavaria after 1988, and until this report, increased surveillance in neighbouring Austria had not found this organism. We propose that the strain may have recently spread from Bavaria to Austria. Although SF EHEC O157:H- strains are still rare, they may represent a considerable health threat as they can spread from farm animals to humans and between humans.