Speaker
Description
Phages are major vehicles for horizontal gene transfer in the human pathogen Staphylococcus aureus and promising agents for the treatment of antibiotic resistant infections. All currently known Staphylococcus phages use wall teichoic acid (WTA), a bacterial cell wall glycopolymer, as their receptor, such that loss of WTA can lead to phage escape. We found that Silviavirus Remus can bind and infect S. aureus even in the absence of WTA, albeit with decreased efficiency, indicating that the phage uses an additional receptor. Analysis on phage resistant mutants of S. aureus revealed disruptions of the cell-wall bound peptidoglycan transglycosylase IsaA. Clean deletion of IsaA in a WTA-negative background confirmed the extracellular enzyme as the additional S. aureus Silviavirus receptor, which was further confirmed via detection of direct binding between phage Remus and IsaA. These findings illuminate the molecular specificities of S. aureus-phage interactions with important implications for future phage therapies.
