Razie Kamalidolatabadi - Department of Bacteriology and Virology, Faculty of Medicine, Isfahan University of Medical Science, Isfahan, Iran
Hossein Fazeli - Department of Bacteriology and Virology, Faculty of Medicine, Isfahan University of Medical Science, Isfahan, Iran

Background and Aim : Among the pathogenic bacteria AIEC (Adherent Invasive E.coli) pathovars have special attention in colorectal cancer. It was identified in ۱۹۹۹ by Boudeau. According to the WHO, ۲۵% of cancers are caused by infections, wich colorectal cancer being the second leading cause of death in ۲۰۱۸. 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 (۱). Therefore, we decided that by isolating and diagnosing AIEC pathovars from CRC patients and compare with control.Methods : ۶۰ biopsy samples (۳۰ from CRC, ۳۰ from control) were taken. Samples lysed with Triton ۱۰۰-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 (۲).Results : We analyzed ۶۰ biopsies (۳۰ CRC and ۳۰ controls). Bacterial growth, following overnight incubation, was detected in tissue specimens from ۱۷ out of ۳۰ CRC and ۷ out of ۲۳ controls. For AIEC identification, adherent isolates were assayed for invasiveness, and the capacity of the adhesive-invasive isolates to survive and replicate intracellularly was determined over macrophages J۷۷۴. In this way we identified ۱۹AIEC- isolates. Interestingly, their relative abundance was significantly higher in CRC patients (۴۶.۶%; ۱۴/۳۰) than in controls (۱۶.۶%; ۵/۳۰).Conclusion : The studies indicated that Mucosa-Associated AIEC strains are more frequently in CRC than the 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 (۳, ۴). In conclusion, our study showed a high prevalence of AIEC in biopsies of colon cancers.

Mucosa-Associated adherent-invasive Escherichia coli , Colorectal cancer