The altered cell cycle progression was consistent with induction of a DNA damage response, as infection with wild-type S. Javiana resulted in 43% of cells having at least four p53-binding protein 1 (53BP1) foci that colocalized with phosphorylated histone 2AX (γH2AX) foci (both DNA damage markers), compared to just 5% in uninfected control cells (P = 0.0113) or in cells infected with the ΔcdtB strain (P = 0.0213; Fig. 1C and D). This evidence concerns the gene TP53BP1 and infection.