Elevated intracellular levels of iron in host cells promotes Burkholderia pseudomallei infection

Background: Burkholderia pseudomallei is the causative agent of melioidosis. The disease is endemic in northeast Thailand. Several studies have reported the effect of iron-overloaded environment in promoting bacterial infection. However, little is known about the effect of host cell iron elevation on melioidosis.

Objective: We investigated the impact of increased host cell iron levels on B. pseudomallei infection.

Methods: HeLa and A549 cell monolayers were supplemented with ferrous sulfate (FeSO₄) and ascorbic acid to increase intracellular iron levels. The iron elevated host cells were infected with B. pseudomallei and examined for plaque formation, cell invasion, intracellular survival and multinucleated giant cell (MNGC) formation and compared to bacteria infecting control cells.

Results: The ability of B. pseudomallei to form plaques in iron supplemented HeLa cells and to invade iron supplemented A549 cells was significantly higher. Furthermore, the intracellular survival of B. pseudomallei and the ability to induce MNGC formation in iron-supplemented host cells was greater than in infected control cells.

Conclusion: Elevation of iron levels in host cells promotes B. pseudomallei infection.