ExPEC-typical virulence associated genes correlate with successful colonization by intestinal E. coli in a small piglet group

Studying the transmission of Escherichia coli from a sow to five of her piglets, we observed one E. coli clone dominating the coliform flora in piglets, especially after weaning. This haemolytic cloneH1 had a virulence gene profile very similar to extraintestinal E. coli (ExPEC), including genes coding for P fimbriae and several iron acquisition systems and an affiliation to the phylogenetic B2 group. In general, we show that the presence of numbers of ExPEC-typical virulence associated genes (VAFs) in clones correlate with their colonization success in piglets. We conclude that virulence associated genes typical for ExPPEC also support intestinal colonization in healthy pigs. Faeces of healthy domestic pigs can harbour high numbers of ExPEC-similat E. coli and are suggested to have potential risk for transmission of such bacteria to other hosts.