The Evolutionary Genomics of Host Specificity in Staphylococcus aureus

Staphylococcus aureus is an important human bacterial pathogen that has a cosmopolitan host range, including livestock, companion and wild animal species. Genomic and epidemiological studies show that S. aureus has jumped between host species many times over its evolutionary history. These jumps have involved the dynamic gain and loss of host-specific adaptive genes, usually located on mobile genetic elements. The same functional elements are often consistently gained in jumps into a particular species. Further sampling of diverse animal species is likely to uncover an even broader host range and greater genetic diversity of S. aureus than is already known, and understanding S. aureus host specificity in these hosts will mitigate the risks of emergent human and livestock strains. Based on its broad host range, S. aureus can be described as a generalist pathogen.On short evolutionary timescales, however, strains are host specialists.S. aureus is capable of rapid adaptation to a wide range of hosts, mainly through the acquisition of mobile genetic elements (MGEs).Host shifts are a dynamic and a regular feature of S. aureus evolution.A large diversity of animal strains of S. aureus remain uncharacterized.Inferring the host ecology of strains of S. aureus from their genomes will aid surveillance and diagnostics