Figure 7.

Serial sampling experiment to investigate bacterial dissemination in brains of C57BL/6 mice at different challenge doses of aerosolized Burkholderia pseudomallei strain ATS2021, the causative strain in an outbreak of 4 cases, 2 of them fatal, in the United States in 2021. C57BL/6 mice were estimated to have inhaled various doses of aerosolized Burkholderia pseudomallei ATS2021 on day 0: A) 107 CFU, B) 1,150 CFU, and C) 4,490 CFU. A subset of mice was then deeply anesthetized for a terminal blood collection, euthanized, and then brains were removed to determine the bacteriologic burden in each brain at each time point indicated. N = 4 for each time point. The CFU burden is shown for each mouse, depicted as a black circle; geometric mean is depicted with the horizontal bar. The brain homogenates were exposed to ≈21 kGy of gamma radiation, proven sterile, and then subjected to the B. pseudomallei capsule-specific immunodiagnostic assay. The MFI of each mouse is depicted by a red circle, and the geometric mean is depicted with the horizontal bar. Limit of detection is ≈5 CFU/organ. The detection of capsule in the irradiated brain homogenate is depicted in red and is displayed as MFI. MFI, mean fluorescent intensity.