Colibactin

Colibactin is a genotoxic metabolite produced by Escherichia coli and other Enterobacteriaceae ("enteric bacteria") believed to cause mutations leading to colorectal cancer and the progression of colorectal cancer. Colibactin is a polyketide peptide that can form interstrand crosslinks in DNA. Colibactin is only produced by bacterial strains containing a polyketide synthase genomic island (pks) or clb biosynthetic gene cluster. About 20% of humans are colonized with E. coli that harbor the pks island.

Colibactin forms DNA inter-strand cross-links by alkylation of adenine moieties on opposing DNA strands. It induces lytic development in certain bacteria that contain prophages.