The Yersinia high-pathogenicity island (HPI) encodes an iron uptake system mediated by the siderophore yersiniabactin (Ybt) and confers the virulence of highly pathogenic Yersinia species. This HPI is also widely distributed in human pathogenic members of the family of Enterobacteriaceae, above all in extraintestinal pathogenic Escherichia coli (ExPEC). In the present study we demonstrate a highly significant correlation of a functional HPI and extraintestinal virulence in E. coli. Moreover, using a mouse infection model, we show for the first time that the HPI contributes to the virulence of ExPEC.