Infection experiments using the ICEKp + clb- strain NTUH-K2044 show that it is highly virulent despite the lack of colibactin13, but virulence in this strain is likely also influenced by additional copies of the iro and rmpA virulence loci that are not found in the majority of CG23 Kp (Figs. 1 and 2, also see below for discussion of other virulence determinants). Here, NPPA is linked to infection.