Bacterial uptake, intracellular survival and replication of Burkholderia strains in mouse macrophages. J774A.1 macrophages were exposed to Burkholderia strains at an MOI of 10 and the mean numbers of intracellular bacteria were determined at 2, 4, 6, 8 and 12 hrs post infection. (A) Uptake of bacteria by macrophages as determined by bacterial counts 2 hrs post infection relative to the input numbers. (B-D) Intracellular survival and replication of B. pseudomallei (Bps; panel B), B. thailandensis (Bt; panel C) and B. oklahomensis (Bo; panel D) in J774A.1 macrophage cells. Error bars represent the standard error of the mean. All infections were performed as three independent experiments, each with three technical replicates. The insert in panel C represents individual bacterial counts and the mean value at 12 hrs post infection with different B. thailandensis strains.