The extra-intestinal avian pathogenic Escherichia coli strain BEN2908 invades avian and human epithelial cells and survives intracellularly.

Extra-intestinal pathogenic Escherichia coli (ExPEC) strains are responsible for a wide range of diseases in humans and animals. Using in vitro invasion assays and transmission electron microscopy, we showed that BEN2908, an ExPEC strain of avian origin (also termed APEC for Avian Pathogenic E. coli), is able to usurp cellular endocytic pathways to invade A549 human type II pneumocytes and LMH avian hepatocytes where it is able to survive over several days. Although type 1 fimbriae are the major adhesin of BEN2908, proportions of adherent fimbriated or afimbriated bacteria that entered cells were comparable. Internalization of BEN2908 into human pneumocytes reinforces previous studies indicating that APEC strains could represent a zoonotic risk.