In the prolonged human battle against colorectal cancer, could genotoxic Escherichia coli be in the front line of the war?

Objective To find an association between colorectal cancer (CRC) and genotoxic Escherichia coli isolated from the human microbiota. Patients and methods A total of 150 patients (65 males and 85 females) were recruited from the surgical endoscopy unit in the Medical Research Institute Hospital, Alexandria, Egypt. They were divided into two groups: group I included 100 neoplastic patients (benign and malignant), and group II included 50 nonneoplastic patients. After DNA extraction, real-time PCR was performed to detect the presence of pks island in E. coli strains. Result The number of males (57.4%) among patients with malignant neoplastic illness was higher than the number of females (42.6%). Overall, no statistical difference was observed between the studied groups regarding sex (P=0.059). Malignant neoplastic diseases were more common in patients above 45 years. Old age in malignant patients showed a high statistical significance compared with nonmalignant patients (P <= 0.001). The pks+E. coli was detected in colorectal biopsies using the clbB gene as a surrogate marker of the whole pks island. The current study demonstrated that the prevalence of pks-positive E. coli was significantly higher in patients with malignant neoplastic disease than benign neoplastic and nonneoplastic ones (P=0.002). Conclusion pks+E. coli may act as a tumor promoter for CRC and could be used as a predictive marker for CRC development. In addition, the pks+E. coli molecular identification may be of a good value in decreasing missed lesions during conventional colonoscopy.