Fig. 4.

S. Typhi survival does not involve an intracellular state. (A) Effect of antibiotic added at day 10 to evaluate growth of A. castellanii grown by itself (square), with S. Typhi (circle), or with S. Typhi and gentamicin addition (triangle). (B) Growth of S. Typhi alone (square) or with A. castellanii and gentamicin added at day 10 (triangle). Survival by direct cell-cell contact was evaluated by transwell experiments. S. Typhi was inoculated in the upper compartment, and A. castellanii was inoculated in the lower compartment. (C) Growth of amoebae with (triangle) or without (square) bacteria in the upper compartment. (D) Growth of bacteria with (triangle) or without (square) amoebae in the lower compartment. Results are the means ± standard errors of the means of three independent experiments. Asterisks indicate a significant difference (P < 0.05).