Adherent-invasive Escherichia coli phenotype displayed by intestinal pathogenic E. coli strains from cats, dogs, and swine.

The adherent-invasive Escherichia coli (AIEC) pathotype, which has been associated with Crohn's disease, shows similar traits to human and animal extraintestinal pathogenic E. coli (ExPEC) with respect to their phylogenetic origin and virulence gene profiles. Here, we demonstrate that animal ExPEC strains generally do not share the AIEC phenotype. In contrast, this phenotype is very frequent among animal intestinal pathogenic E. coli (InPEC) strains, particularly of feline and canine origin, that genetically resemble ExPEC. These results strengthen the particular identity and disease specificity of the AIEC pathotype and the putative role animals might play in the transmission of AIEC-like strains to humans.