Figure 2. Comparison of survival within macrophage cells.

RAW264.7 cells were infected with Salmonella cells grown overnight in LB via MOI of 50. After infection initiation by centrifuging the bacteria onto the cell monolayers at 1,000×g for 5 min, cells were incubated at 37°C with 5% CO₂ for 30 min, treated with gentamicin (100 µg/ml) for 1 h, and incubated in DMEM with gentamicin (20 µg/ml) for the remainder of the test. Macrophage cells were lysed using 1% Triton-X at 1.5 h (A) and 18 h (B) post-infection and the intracellular bacteria were enumerated by serial dilution of cell lysates. The data shown represents the mean and standard deviation of three individual experiments.