Escherichia coli is assumed to be involved in inflammatory bowel disease (IBD) by many authors. The present Short Report was aimed at analyzing E. coli population isolates from ileal samples collected from 4 CD and 3 non-CD (control group) diagnosed pediatric patients. A total of 539 mu- cosa-associated E. coli strains were characterized by: Random Amplified Polymorphic DNA (RAPD), adhesive and virulence factors, and for their phylogenetic groups. A significant separation be- tween RAPD profiles of the two CD and non-CD cohorts (P < 0.0001), along with a significant reduc- tion of intra-species genomic variability in E. coli populations isolated from CD group (P < 0.0001) was found as assessed by Dice index, indicating a different selective pressure in CD intestinal ha- bitat. A predominance of phylogenetic group A was found in control subjects (P < 0.0001). Results on adhesive and virulence factors evidenced peculiar genes significantly related to CD E. coli pop- ulations (K1, IbeA) (P < 0.0001) and to total DNA from biopsy specimens K1 (P < 0.0001). Results suggest that among E. coli population, particular variants may be favorite in the intestinal habitat of CD pediatric patients. These genotype variants could represent the genetic background that, via evolutionary phenomena driven by a persistent inflammatory state, may evolve in Adherent Inva- sive Escherichia coli (AIEC) like strains found in adult CD patients.
