Origins of the <i>E. coli</i> Strain Causing an Outbreak of Hemolytic–Uremic Syndrome in Germany

Our findings suggest that horizontal genetic exchange allowed for the emergence of the highly virulent Shiga-toxin-producing enteroaggregative E. coli O104:H4 strain that caused the German outbreak. More broadly, these findings highlight the way in which the plasticity of bacterial genomes facilitates the emergence of new pathogens.