Objective      To establish a cell model of human acute mononuclear leukemia cells THP-1 are infected  by Burkholderia pseudomallei (BP) and then determine the effect of polyethylene glycol 3350 (PEG3350) on bacteria-affected cells and intracellular survival. To compare the infection characteristics of BP and  its attenuated strain

Burkholderia thailandensis (BT) to lay the foundation of the infection  mechanism of the bacterium.       Methods      The growth curves of  BP and BT were drawn to probe their proliferation rule. Transmission electron microscopy was used to observe the ultra-structure pathological changes of the number of intracellular bacteria and the infected host cells for the reaction of the bacteria and host cells. Plate counting was tested for bacterial colonies at different hours after invasion to analyze the intracellular growth of bacteria. The cytokines in the supernatant of the infected cells and patients’ serum samples were detected to evaluate the reactivity of host cells and the effect of PEG3350 on the bacteria-affected cells and intracellular survival. The inflammatory responses of infected cells to BP and BT strains were contrasted and analyzed. Thereby the stability of this model was evaluated.       Results       The growth curves

phase-infected characteristics

ultra-structure pathological impairments of BP and BT strains were revealed in this study. During the detection of cytokines

TNF-α contents in the supernatant of the cells infected by 2 strains of bacteria reached the peak in the infected metaphase

the exudation of IL-6 contents in the supernatant infected by BP presented 2 peaks

while

the exudation of IL-6 contents of the cells infected by BT and the effect of cytokines by PEG3350 were more complex. In addition

no definite rule was found in the detection of cytokines in patients’ serum. There was no obvious relationship of the cytokines with clinical outcomes.       Conclusion      The model of BP-infected THP-1 cells is constructed successfully in this study. The mechanism of BP infecting the host cells is obtained primarily

which founding a precondition for the interaction between this pathogenic bacteria and host cells in the further study.