Diffusely adherent and cyclomodulin- positive Escherichia coli are associated with colon diseases

Abstract

Any alteration in gut microbiome may result in colonization of some pathobionts and consequently some colon diseases. The present study was performed to determine association between E.coli pathobionts (cyclomodulin positive and afa-C + diffusely adherent E.coli) and also some characteristics of them in patients with colon diseases. Stool specimens were obtained from patients referred to colonoscopy centers of university hospitals of Yazd and Kerman, Iran. Totally 67 patients voluntarily joined the study as target group (21 case of colorectal cancer and 46 case of inflammatory bowel disease) as well as 67 healthy individuals. Stool samples were screened for Escherichia coli isolates by culture technique. Cyclomodulin encoding genes (clbN, cnf, cdt and cif) as well as afa-C, were tracked by PCR assay. Phylogrouping, virulence gene screening, antibiotic susceptibility evaluation and biofilm formation assessment were also performed. Results showed clbN, cnf and afa-C + DAEC were significantly associated with CRC. The latter was also associated with IBD (p < 0.05). Most of the isolates from patients group, belonged to B2 phylogroup. Iron uptake related genes were significantly associated with patients. Antibiotic resistance and biofilm formation were not significantly associated with any studied groups. In conclusion, this study provides primarily data about the status of some important E.coli pathobionts involved in colon diseases. It appears that afa-C + DAEC was more associated with colon diseases so it could be proposed as a putative marker for screening procedures. However, as few of specimens were positive for afa-C and cyclomodulins (clb and cnf), definitive conclusion require more comprehensive investigation.