Research Article Mucosa-Associated Escherichia coli in Colorectal Cancer Patients and Control Subjects: Variations in the Prevalence and Attributing Features Roghayeh Nouri, 1,2 Alka Hasani , 2,3 Kourosh Masnadi Shirazi, 4 Mohammad Reza Alivand , 5 Bita Sepehri, 4 Simin Sotoudeh, 4 Fatemeh Hemmati, 1,2 Afshin Fattahzadeh, 4 Babak Abdinia , 6 and Mohammad Ahangarzadeh Rezaee 2,3,7 1 Student Research Committee, Tabriz University of Medical Sciences, Tabriz, Iran 2 Infectious and Tropical Diseases Research Center, Tabriz University of Medical Sciences, Tabriz, Iran 3 Department of Medical Microbiology, Faculty of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran 4 Liver and Gastrointestinal Diseases Research Center, Tabriz University of Medical Sciences, Tabriz, Iran 5 Department of Medical Genetics, Faculty of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran 6 Pediatric Health Research Center, Tabriz University of Medical Sciences, Tabriz, Iran 7 Clinical Research Development Unit of Children Educational, Research and Treatment Center, Tabriz University of Medical Sciences, Tabriz, Iran Correspondence should be addressed to Mohammad Ahangarzadeh Rezaee; rezaee@tbzmed.ac.ir Received 1 August 2021; Revised 30 September 2021; Accepted 26 October 2021; Published 9 November 2021 Academic Editor: Tingtao Chen Copyright © 2021 Roghayeh Nouri et al. is is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Accumulating evidence indicates that specific strains of mucosa-associated Escherichiacoli (E.coli) can influence the development of colorectal carcinoma. is study aimed to investigate the prevalence and characterization of mucosa-associated E.coli obtained from the colorectal cancer (CRC) patients and control group. At two referral university-affiliated hospitals in northwest Iran, 100 patients, 50 with CRC and 50 without, were studied over the course of a year. Fresh biopsy specimens were used to identify mucosa-associated E.coli isolates after dithiothreitol mucolysis. To classify the E.coli strains, ten colonies per sample were typed using enterobacterial repetitive intergenic consensus-based PCR (ERIC-PCR). e strains were classified into phylogroups using the quadruplex PCR method. e PCR method was used to examine for the presence of cyclomodulin, bfp, stx1, stx2, and eae- encoding genes. e strains were tested for biofilm formation using the microtiter plate assay. CRC patients had more mucosa- associated E. coli than the control group (p < 0.05). Enteropathogenic Escherichia coli (EPEC) was also found in 23% of CRC strains and 7.1% of control strains (p < 0.05). Phylogroup A was predominant in control group specimens, while E. coli isolates from CRC patients belonged most frequently to phylogroups D and B2. Furthermore, the frequency of cyclomodulin-encoding genes in the CRC patients was significantly higher than the control group. Around 36.9% of E.coli strains from CRC samples were able to form biofilms, compared to 16.6% E. coli strains from the control group (p < 0.05). Noticeably, cyclomodulin-positive strains were more likely to form biofilm in comparison to cyclomodulin-negative strains (p < 0.05). In conclusion, mucosa- associated E. coli especially cyclomodulin-positive isolates from B2 and D phylogroups possessing biofilm-producing capacity colonize the gut mucosa of CRC patients. 1. Introduction Colorectal cancer (CRC) is the world’s third most common cancer and the second leading cause of cancer death [1]. Because of its high morbidity and mortality rate, CRC is an important public health issue [2]. Mutations that occur in tumor suppressor genes, oncogenes, and genes related to DNA repair mechanisms can lead to CRC. Depending on the Hindawi Canadian Journal of Infectious Diseases and Medical Microbiology Volume 2021, Article ID 2131787, 8 pages https://doi.org/10.1155/2021/2131787