The cdpA mutant was aflagellate and did not exhibit swimming motility. Transmission electron micrographs of B. pseudomallei KHW (A), cdpA mutant (B), and the complemented cdpA mutant (C). The cdpA mutant was aflagellate and elongated compared to wild-type B. pseudomallei KHW. Flagella were present in the complemented cdpA mutant (C). Scale bars: panel A, 2 μm; panels B and C, 1 μm. Arrows indicate flagella. Wild-type B. pseudomallei KHW (D) and the complemented cdpA mutant (F) exhibited swimming motility in semisolid agar, but the cdpA mutant was nonmotile (E).