<i>B. pseudomallei</i> are resistant to C3 deposition by the alternative pathway of complement.

<p><i>B. pseudomallei</i> and <i>B. thailandensis</i> were incubated with the indicated serum concentrations in the presence or absence of MgEGTA or EDTA, washed, and stained with an anti-human C3 FITC-conjugated antibody. Samples were analyzed by flow cytometry and the data reported as mean fluorescence intensity (MFI). The bars represent the mean±SEM of three separate experiments performed with duplicate samples. The single asterisk (*) indicates a statistically significant increase (<i>P</i>≤0.05) over unopsonized bacteria. The double asterisks (**) indicate a statistically significant difference (<i>P</i>≤0.05) between <i>B. pseudomallei</i> and <i>B. thailandensis</i> values.