No evidence of the Shiga toxin-producing E. coli O104:H4 outbreak strain or enteroaggregative E. coli (EAEC) found in cattle faeces in northern Germany, the hotspot of the 2011 HUS outbreak area

The faecal samples contained neither the HUS outbreak strain nor any EAEC. As the current outbreak strain belongs to ST678 and displays an en-teroaggregative and ESBL-producing phenotype, we additionally screened selected strains for ST678 as well as the aggregative adhesion pattern in HEp-2 cells. However, we were unable to find any strains belonging to ST678 or showing an aggregative adhesion pattern. A high percentage of animals (28%) shed STEC, corroborating previous knowl-edge and thereby proving the validity of our study. One of the STEC also harboured the LEE pathogenicity island. In addition, eleven animals shed ESBL-producing E. coli.While we are aware of the limitations of our survey, our data support the theory, that, in contrast to other Shiga-toxin producing E. coli, cattle are not the reservoir for the O104:H4 outbreak strain or other EAEC, but that the outbreak strain seems to be adapted to humans or might have yet another reservoir, raising new questions about the epidemiology of STEC O104:H4.The month of May 2011 marked the beginning of an outbreak of haemolytic uremic syndrome (HUS) caused by an unusual Shiga toxin-producing E. coli (STEC) O104:H4 strain, belonging to the HUSEC041 clone (HUS-associated enterohaemorrhagic E. coli) because of this specific serotype [1]. The strain, which was found to be of sequence type (ST) 678 rendered many ill and also claimed several lives in Germany. The epicentre of the outbreak was Northern Germany, from where it has spread throughout Germany and beyond, to other European countries [2-4]. With a predominance of infection in adult women and more than 800 cases of haemolytic uremic syndrome (HUS) accompanied with central nervous system complications, this outbreak is unusual. While the reasons for this are currently unknown, it has already been proven that the outbreak strain has an unusual genome make up, as it shows a strong similarity to an enteroaggregative E. coli (EAEC) of the same serotype, which was prev