The virulence plasmid of Yersinia, an anti-host genome

Abstract

Invasive pathogenic bacteria have in common the capacity to overcome the defense mechanisms of their animal host and to proliferate in its tissues. They each have their own life-style and target organs and cause a variety of symptoms and diseases, which suggested the existence of great diversity among the bacterial virulence strategies. However, recent data contradict this view and reveal the existence of major virulence mechanisms in various pathogenic bacteria. One is the release of A-B toxins as exemplified by Bordetella pertussis and Bacillus anthracis. Another was discovered more recently in a number of bacterial pathogens. By this mechanism, sometimes referred to as type III, extracellular bacteria that are in close contact with a eukaryotic cell deliver bacterial proteins into the cytosol of this cell. The Yop system of Yersinia spp., which we describe in this review, represents an archetype for this new mechanism. The other animal pathogens with related systems are Salmonella spp., Shigella spp., enteropathogenic Escherichia coli (EPEC), Pseudomonas aeruginosa, Chlamydia psittaci, and Bordetella spp. Related systems are also found in the plant pathogens that elicit the so-called hypersensitive response, such as Erwinia amylovora, Pseudomonas syringae, Xanthomonas campestris, and Ralstonia solanacearum.