Staphylococcus sciuri bacteriophages double-convert for staphylokinase and phospholipase, mediate interspecies plasmid transduction, and package mecA gene

Staphylococcus sciuri is a bacterial pathogen associated with infections in animals and humans, and represents a reservoir for the mecA gene encoding methicillin-resistance in staphylococci. No S. sciuri siphophages were known. Here the identification and characterization of two temperate S. sciuri phages from the Siphoviridae family designated phi575 and phi879 are presented. The phages have icosahedral heads and flexible noncontractile tails that end with a tail spike. The genomes of the phages are 42,160 and 41,448?bp long and encode 58 and 55 ORFs, respectively, arranged in functional modules. Their head-tail morphogenesis modules are similar to those of Staphylococcus aureus phi13-like serogroup F phages, suggesting their common evolutionary origin. The genome of phage phi575 harbours genes for staphylokinase and phospholipase that might enhance the virulence of the bacterial hosts. In addition both of the phages package a homologue of the mecA gene, which is a requirement for its lateral transfer. Phage phi879 transduces tetracycline and aminoglycoside pSTS7-like resistance plasmids from its host to other S. sciuri strains and to S. aureus. Furthermore, both of the phages efficiently adsorb to numerous staphylococcal species, indicating that they may contribute to interspecies horizontal gene transfer.