Fig. 2.

Interaction (adhesion and invasion) and invasion assays. The 11168H wild-type, Cj1556 mutant, and Cj1556 complement (Cj1556 comp) strains were cocultured with Caco-2 intestinal epithelial cells for 3, 6, or 24 h. The Caco-2 cells either were lysed and the numbers of interacting bacteria were assessed (A) or were incubated with gentamicin (150 μg/ml) for 2 h to kill extracellular bacteria and then lysed, and the numbers of intracellular bacteria were assessed. The asterisks denote a statistically significant difference (*, P < 0.05; ***, P < 0.001) for the Cj1556 mutant compared to the 11168H wild-type strain.