The ribosome rescue inhibitor KKL-10 exhibits exceptional antimicrobial activity against both attenuated and fully virulent strains of F. tularensis . The minimum inhibitory concentration (MIC) against F. tularensis strain LVS and Schu S4 are 0.12 and 0.48 μg/mL, respectively. KKL-10 arrests intracellular growth of F. tularensis during all stages of infection. KKL-10 does not affect macrophage viability or function. KKL-10 produces cytotoxic effects of less than 5% at concentrations up to 17.5 μg/mL. The combination of IFN-γ stimulation and KKL-10 activity results in a reduction of the bacterial load by >99.9%. KKL-10 is also able to inhibit growth of F. tularensis inside eukaryotic cells and show no toxicity to HepG2 cells.