The pks genomic island encodes non-ribosomal peptide synthase (NRPS), polyketide synthases (PKS), and hybrid NRPS/PKS synthetase. This genomic island is mainly found in the members of the family Enterobacteriaceae, and is especially common in Escherichia coli of phylogroup B2 while frequently coexisting with other virulence factors. The pks-positive E. coli is able to synthesize colibactin, a genotoxic chemical compound. Thus, this pks-positive bacteria may induce the breaking of DNA double-strand and chromosomal instability, which lead to senescence and apoptosis of cells. As a result, pks-positive E. coli is positively associated with the occurrence of diseases such as colorectal neoplasms, neonatal meningitis, and septicemia. Epidemiological studies have also confirmed that pks-positive E. coli is associated with a variety of diseases. However, the exact pathogenic mechanism of pks-positive E. coli is still not understood. Despite its genotoxicity, the pks-positive E. coli also exhibits some positive effects including anti-inflammatory, analgesic, and antibiotic abilities. Therefore, the biological role of pks-positive E. coli is complicated. In this review, an overview of the pks genomic island and its prevalence in Enterobacteriaceae, as well as the biological function of pks-positive E. coli is described, aiming to provide references for further researches.

Polyketide synthases; Enterobacteriaceae; Colorectal neoplasms; Laboratory techniques and procedures