The Role of clbF in the Pathogenicity of Avian Pathogenic Escherichia coli

The genotoxin colibactin, a complex secondary metabolite, targets eukaryotic cell cycle machinery and contributes to neonatal sepsis and meningitis. Avian pathogenic Escherichia coli (APEC) XM, which produces this genotoxin, is an agent of poultry diseases with zoonotic potential. In this study, we confirmed that clbF was necessary for the APEC XM strain to produce colibactin, but it did not affect the growth, adhesion, or invasion of cells. Deletion of clbF substantially diminished both virulence and systemic dissemination, but it also changed the gene expression of the antiserum survival factor, adherence and invasion, iron acquisition genes, and the secretion system. In conclusion, clbF is necessary for the synthesis of the genotoxin colibactin and affects the development of APEC meningitis in mice.