Antibiotic mediated intracellular killing of B. mallei infected J774A.1 murine macrophages. Bacteria were added at an MOI of 25:1 and incubated for 2 hours at 37°C with 5% CO2 followed by incubation with 100 × MIC levofloxacin (black bars), ceftazidime (white bars) or media only (crossed bars). Media in control wells contained 250 μg/ml kanamycin for first 2 h postinfection and 100 μg/ml kanamycin for the rest of the assay to prevent the growth of extracellular bacteria. At 2, 4 and 8 h post treatment, cells were washed and lysed with 0.1% Triton X-100, followed by serial 10-fold dilutions plated on LBG plates and incubated at 37°C for 2 days for CFUs determination. Experiment performed twice in triplicate. Errors bars represent mean ± SEM. * P < 0.05 significant difference between time 0 and all time points in levofloxacin treatment, ** P < 0.01 significant difference between time 0 and all time points in ceftazidime treatment.