Among the pathogenic bacteria AIEC (Adherent Invasive E.coli) pathovars have special attention in colorectal cancer. It was identified in 1999 by Boudeau. According to the WHO, 25% of cancers are caused by infections, which colorectal cancer being the second leading cause of death in 2018. AIEC is an effective pathogen in CRC.Ability to bind and invade the M epithelial follicle-associated (FAE) cells, the ability to survive and replicate within macrophages allow the bacterium to the formation of granulomas and malignancy (1). Therefore, we decided that by isolating, diagnosing AIEC pathovars and determine characteristics of them from CRC patients and compare with control

60 biopsy samples (30 from CRC, 30 from control) were taken. Samples lysed with Triton 100-X% to release intracellular E. coli isolates. The isolates confirmed by phenotypic and molecular methods. To distinguish AIEC pathovar, phenotypic tests; Adhesion assays, Invasion assays, Gentamicin protection assays, and survival and replication in macrophage (2).

We analyzed 60 biopsies (30 CRC and 30 controls). We identified 19AIEC- isolates. Interestingly, their relative abundance was significantly higher in CRC patients (46.6%; 14/30) than in controls (16.6%; 5/30). The invasion level were 0.52 ± 0.15 and 1.68 ± 0.27 in control and CRC patients respectively. survival level were 47.55 ± 15.74 and 519.55 ± 130.82 in control and CRC patients respectively.

The studies indicated that Mucosa-Associated AIEC strains are more frequently in CRC than the control. These isolates from CRC patients showed higher invasiveness, and survival capability than those from control. One explanation of the high prevalence of AIEC in CRC could be that changes in the host mucosa receptor repertoire have an effect on the bacterial population associated with mucosa. Previous studies reported higher numbers of AIEC in CRC than controls (3, 4). In conclusion, our study showed a high prevalence of AIEC in biopsies of colon cancers