Transient infection with colibactin-producing bacteria (Clb+Cnf+ and Clb+Cnf-) caused cell cycle arrest, apoptosis induction and megalocytosis in HT-29 cells (Figure 2a, as expected.19,41,42 Clb-Cnf+ and Clb-Cnf- +pBK-cnf were able to induce accumulation of cells in both the S and G2/M phases compared to uninfected cells (Figures 2a and Supplemental Figure S3A). The gene discussed is PBK; the disease is infection.