Current understanding of the genetic diversity of Brucella, an expanding genus of zoonotic pathogens

Brucella species are responsible for brucellosis, one of the world's most widespread zoonotic diseases causing abortion in domestic animals and a potentially debilitating infection of man. Despite the identification of a number of distinct species within the genus with differing host preferences and pathogenicity it has been known for many years that members of the genus are genetically homogeneous. However, since the start of the millennium the application of new technologies to the group has resulted in rapid advances in the understanding of Brucella diversity and, after many years of inactivity, a process of expansion of the genus is underway. This review summarises the current state of knowledge in this area and outlines how this informs understanding of the taxonomy and evolution of the group and is enabling the development of increasingly sophisticated molecular typing tools.