Transmission electron micrograph of intracellular B. pseudomallei within U937 cells. (A) B. pseudomallei-infected U937 cells demonstrating oncotic-like morphology and disruption of cell membrane. ×7000 (B) Internalised B. pseudomallei within membrane-bound phagosome (arrowed) were observed at early stage of intracellular infection. ×8000 (C) Loss of phagosome membrane was clearly visible and free bacteria were seen in the cell cytoplasm (arrowed). ×8000 (D) A dividing bacillus in a phagosome with near-intact membrane (arrowed). Some membrane dissolution can be seen close to the ends of the bacterial cell. ×8000.