Determination of Colibactin Island in Novel Escherichia Fergusonii Isolated from Colorectal Cancer Case

Colorectal cancer is the second most common cause of cancer-related death. In our current study, 62 bacterial samples were isolated from 55 biopsies from patients undergoing gastrointestinal endoscopy and surgical procedures. The majority of these biopsies were from patients with colorectal cancer, while the smallest number were from patients with gastric cancer. It is worth noting that 11 colorectal and gastric biopsies failed to culture on culture media. The results showed that E. coli was the most prevalent among the Gram-negative isolates obtained, accounting for 46 of the total bacterial isolates.

 Escherichia fergusonii was obtained from an elderly woman who had colon cancer and underwent surgery to remove the tumor. Using traditional PCR, Escherichia fergusonii was molecularly identified as one of the isolates that had the colibactin-encoding genes (clbA. clbB, clbN, clbQ). Thus, this was considered the first local and global isolate containing these genes. The 16S rRNA gene sequences were used to prove the diagnosis of E. fregusonii and compared with those of the National Center for Biotechnology Information (NCBI).

Deposition of the sequences of 16S rRNA at GenBank, under the accession number PV628355.1, and then the strain was given abbreviated name IAA. The phylogenetic tree was conducted to obtain the relationship between the pv628355 isolate and other Iraqi isolates and the result showed a high relationship between IAA PV628355 with IRQBAS114 LC647818.