Horizontal transfer and phylogenetic distribution of the immune evasion factor .

Methicillin-resistant (MRSA), a major human pathogen, uses the prophage-encoded gene as an important immune evasion factor. TarP glycosylates wall teichoic acid (WTA) polymers, major surface antigens, to impair WTA immunogenicity and impede host defence. However, phages appear to be restricted to only a few MRSA clonal lineages, including clonal complexes (CC) 5 and 398, for unknown reasons. We demonstrate here that -encoding prophages can be mobilized to lysogenize other strains. However, transfer is largely restricted to closely related clones. Most of the non-transducible clones encode , which generates a WTA glycosylation pattern distinct from that mediated by TarP. However, does not interfere with infection by phages. Clonal complex-specific Type I restriction-modification systems were the major reasons for resistance to phage infection. Nevertheless, phages were found also in unrelated clones indicating that has the potential to spread to distant clonal lineages and contribute to the evolution of new MRSA clones.