Identification of Acinetobacter baumannii Type VI Secretion System Targets and Toxins

The pathogen Acinetobacter baumannii utilises its T6SS to kill rival bacteria. We identified three toxins required for bacterial killing as well as the immunity proteins that protect A. baumannii from killing its sister cells. One of these toxins was confirmed to act by degrading target cell DNA. Each of these three toxins was found to be dependent upon a co-encoded VgrG protein for its secretion. Finally, analysis of the genomes of a variety of A. baumannii genomes identified significant diversity among potential secreted toxins at the strain level providing insight into how strains of A. baumannii have become globally distributed.