Escherichia coli Biomarker Types in Colorectal Cancer Patients

Abstract

Colorectal cancer is the second leading cause of cancer in the globe; increasing evidence suggests that the intestinal microbiota is a key factor associated with carcinogenesis of colorectal cancer (CRC) and colonic polyps. This study was conducted on 50 adult patients of both gender. These patients were proved colorectal cancer of different stages, and they were attending gastrointestinal center in Ramadi city, Gastroenterology and Liver Disease Center at Medical City Hospital Baghdad, during the period extended from November to February 2021. Thirty-five biopsies were taken from patients with colorectal cancer diagnosed in colonoscopy, and fifteen (15) stool specimens were taken from them. Each specimen was cultivated on blood agar, MacConkey agar, at 37°C for 24 hours. Then bacterial colonies were studied grossly, their size, color, elevation, texture, and odor; dry, stained smear was stained with Gram stain. A part of the test colony was submitted to biochemical investigation using a suitable sterile medium for each test. The bacterial diagnosis was confirmed using the VITIC system. For molecular research, Escherichia coli isolates were purified and maintained frozen at-20°C in a brain heart infusion broth containing 20% glycerol. Another 50 control adult, with normal colonoscopy from both genders. A stool specimen was taken from each control individually and processed as soon as possible in the same way for the patient group. Test E. coli isolated from both patient group and control group were tested for virulence genes different Frequency of 16S ribosomal RNA (16SrRNA) gene, cytotoxic necrotizing factor (CNF) gene, cytolethal distending toxin (CDT) gene, and polyketide synthase (PKS) genes. The Tumor Necrosis Factor (TNF) was measured in sera from patients with CRC and compared to healthy individuals. The genes implicated in carcinogenesis in E. coli strains, such as 16SrRNA, CNF, and CTD, were only found in test isolates of E. coli from patients, indicating that local E. coli containing such genes could become pathogens in such persons, contributing to CRC induction.