FIG. 1.

Invasion of HEp-2 cells by serovar Typhimurium SL1344, serovar Pullorum, and serovar Gallinarum. Bacteria were grown statically at 37°C in Luria broth for 48 h before infecting 5 × 10⁴ HEp-2 cells at a multiplicity of infection of 400 in a 24-well culture dish. After the addition of bacteria, the cell culture plates were centrifuged at 750 × g for 15 min at 25°C. Data are CFU presented as the mean ± standard deviation (error bar) of triplicate wells and are presented as the percentage of the inoculum surviving gentamicin treatment. Data are representative of at least three independent experiments.