Seyed Abolfazl Hosseininasab - Department of Medical Microbiology (Bacteriology & Virology), Afzalipour Faculty of Medicine, Kerman University of Medical Sciences, Kerman, Iran.
Omid Tadjrobehkar - Department of Medical Microbiology (Bacteriology & Virology), Afzalipour Faculty of Medicine, Kerman University of Medical Sciences, Kerman, Iran.
Hengameh Zandi - Department of Microbiology, School of Medicine, Shahid Sadoughi University of Medical Sciences,Yazd, Iran.
Fereshteh Saffari - Medical Mycology and Bacteriology Research Center, Kerman University of Medical Sciences, Kerman, Iran.

BACKGROUND AND OBJECTIVESColorectal cancer (CRC) is one of the most common types of cancer in the world. There are several factors involved in the creation of CRC, such as age, genetic factors, unhealthy behaviors, microbial factors, and inflammatory bowel diseases. E. coli is one of the members of intestinal microflora that may play a prominent role in CRC. In some E. coli strains, there are a set of virulence factors such as cyclomodulins (colibactin and cytotoxic necrotizing factors) and siderophores (such as aerobactin) that can affect the balance of intestinal microbiota and also cause changes in intestinal cells, leading to gastrointestinal malignancies or CRC, over time. The aim of this study was to investigate the frequency of E. coli isolates carrying cyclomodulins and aerobactin genes, in fecal specimens of patients and healthy individuals.MATERIALS AND METHODSIn this study, ۱۳۴ fecal samples including samples from patients with inflammatory bowel disease (IBD) or CRC (n=۶۷) and those from healthy ones (n=۶۷) were collected. The patients were selected from individuals whose disease was diagnosed for the first time and had not received any treatment (new cases). Also, they had not taken any antibiotic in the last two weeks before sampling. Isolation and identification of E. coli isolates was performed by culture methods and biochemical tests. Genomic DNA was used for looking for the presence of clbN, cnf۱ and iutA by PCR assay.ConclusionThe presence of E. coli isolates containing cyclomodulins and aerobactin encoding genes, may be proposed in the development of gastrointestinal malignancies and may be used as markers for prediction of CRC. In addition, these factors may be targeted for therapeutics purposes in further researches. However, definite decision needs further studies

E.coli; cyclomodulin; pks; siderophore; colorectal cancer