Interaction of Burkholderia pseudomallei with host macrophages

Abstract

Melioidosis is a disease caused by the Gram-negative bacterium Burkholderia pseudomallei. This disease is endemic in South-east Asia and northern Australia and has been recognized as an emerging infectious disease worldwide. We have focused on the interaction between bacteria and phagocytes, mainly monocytes and macrophages. We found that a virulent strain of B. pseudomallei induces a rapid oncotic death in monocytes, macrophages and dendritic cells through a caspase-1 dependent pathway. We found that the bsa-encoded type III secretion system is involved in the induction of caspase-1-dependent oncosis in macrophages. In addition, we developed an efficient screening protocol based on the in vitro macrophage killing assay to identify transposon mutants with attenuated cytotoxicity. We believe that this novel description of macrophage death induced by B. pseudomallei and identification of new mediators could shed light on the pathogenesis of the bacterium in disease.