Fig. 3.

Intracellular survival assays. The 11168H wild-type, Cj1556 mutant, and Cj1556 complement (Cj1556 comp) strains were cocultured with Caco-2 intestinal epithelial cells (A) or J774A.1 mouse macrophages (B) for 3 h and then incubated with gentamicin (150 μg/ml) for 2 h to kill extracellular bacteria, followed by further incubation with gentamicin (10 μg/ml). The cells were lysed, and the numbers of intracellular bacteria were assessed. The asterisks denote a statistically significant difference (P < 0.05) for the Cj1556 mutant compared to the 11168H wild-type strain.