Mucosa-associated Escherichia coli from B۲ and D phylogroups colonize gut mucosa of colorectal cancer patients

Background and Aim : Colorectal cancer (CRC) is the third most prevalent malignant tumor in the world. Specific strains of intestinal Escherichia coli (E. coli) can influence the development of CRC. This study aimed to determine the phylogroups of mucosa-associated E. coli isolates from CRC patients and control group.Methods : In a prospective study, a total of ۹۶ patients, ۴۸ with CRC and ۴۸ without were studied, between June ۲۰۱۹ and June ۲۰۲۰, from two referral university-affiliated hospitals in northwest Iran. Fresh biopsy specimens obtained by colonoscopy were used to identify mucosa-associated E. coli isolates after mucolysis. The isolates were then classified into phylogroups using quadruplex PCR method.Results : CRC patients had significantly more mucosa-associated E. coli than the control subjects. Phylogroup D was predominant in CRC patients (۴۱.۶۶%), followed by phylogroups B۲ (۳۶.۶۶%), A (۱۵%), and B۱ (۶.۶۶%). Moreover, control group isolates in this study most frequently belonged to phylogroup A (۳۹.۱%), followed by phylogroups B۱ (۱۹.۵۱), D (۱۹.۵۱), B۲ (۱۲.۱۹), E (۴.۸۸) and F (۴.۸۸).Conclusion : Gut mucosa of CRC patients more colonized by B۲ and D phylogroups of mucosa-associated E. coli; therefore, some strains that belonged to this phylogroups may be involved in the pathogenesis of CRC.

Keywords:

E. coli , Colorectal cancer , Phylogroups