FIG. 1.

Cell association (A), entry (B), and intracellular survival (C) of F. tularensis strains in A. castellanii amoebae. Rates of cell association (A) and entry (B) of LVS were arbitrarily set at 1. The intracellular survival rate (C) is represented as the ratio of numbers of CFU recovered at 24 h to those recovered at time zero for each strain. Data points and error bars represent the means and standard deviations, respectively, of the results of assays done in triplicate from representative experiments (**, P ≤ 0.02; *, P ≤ 0.05).