Bacterial infections are a major burden in our healthcare systems. Macrophages and neutrophils are professional phagocytes and are largely employed by the immune system to clear bacterial infections. They use various strategies to destroy bacteria such as the production of degradative enzymes, reactive oxygen species and antimicrobial proteins. To better understand this process we use Dictyostelium discoideum, a professional phagocyte, as a model to study bacterial killing.

We showed that D. discoideum uses two different strategies to eliminate P. aeruginosa. D. discoideum ingests and kills P. aeruginosa in phagosomes. In this case, the putative magnesium pump Kil2 is necessary. In addition, D. discoideum kills P. aeruginosa extracellularly. In this case, the ROS generating NADPH complex NoxA and the amoebapore-like protein A AplA are necessary. These results demonstrate that both killing strategies mobilize different effectors.