Invasive properties, adhesion patterns and phylogroup profiles among Escherichia coli strains isolated from children with inflammatory bowel disease

Abstract

Background: A great deal of evidence indicates a link between Escherichia coli (E. coli) and Crohn's disease in adult patients, but there is lack of information on the association of these bacilli with inflammatory bowel disease (IBD) among children.

Objectives: The study was carried out to determine the distribution of phylogenetic group, the adherence patterns and invasive properties of E. coli isolated from children with IBD and non-IBD chronic bowel diseases.

Material and methods: A total of 22 E. coli isolated from biopsy specimens from children with IBD and 21 E. coli strains obtained from children with indeterminate colitis and intestinal polyps were examined for adherence and internalization to the Int407 cell line. Genes involved in epithelial cell invasion and genes specific to E. coli phylogroups were determined by polymerase chain reaction (PCR).

Results: The undefined adherence pattern predominated among the isolated E. coli, although most of them demonstrated the afaD and aggB genes encoding invasions of diffusely adhering and enteroaggregative E. coli. Regardless of the clinical entity, most E. coli were internalized by Int407 epithelial cells and belonged to the B2 and D phylogroups.

Conclusions: The wide distribution of adhesive E. coli capable of entering Int407 cells but also having genes encoding adhesins and invasins characteristic to pathogenic E. coli strains seems to indicate that these E. coli may represent a large group of pathogenic E. coli strains contributing to chronic intestinal disorders.