IREB2 and Respiratory tract infection: The virulence determinants harbored by this successful clone were represented by siderophores such as enterobactin (entABCDEF, fepABCDG) and yersiniabactin (irp1, irp2, ybtSXQPA, fyuA), their co-presence being associated with an increased risk of respiratory tract infections (Bachman et al., 2011), as well as the operon ecpRABCDE, involved in adherence and biofilm formation.