Evolutionary interplay between Staphylococcus aureus and phages: strategies to target biofilm and overcome bacterial resistance

Recently, S. aureus has been reported to be the second most common pathogen causing lethal antibiotic-resistant infections worldwide. This is mainly due to its ability to form biofilm, in which bacterial cells are more tolerant to antibiotics in comparison to their planktonic counterparts and the selection of bacterial clones resistant to the current antibiotic therapy. The requirement of alternative strategies to antibiotics led phage therapy to emerge as a promising approach to cure difficult-to-treat infections. The great advantage in using phages in infection treatment is not only due to their huge abundance and diversity, but also their ability to target antibiotic resistant strains. At the same time, because of their species-specificity, they do not represent a threat for commensal microbiota. In addition, phages could target and destroy biofilms taking advantage of depolymerase enzymes that may allow phages to penetrate and replicate within the biofilm. The expected outcome of this PhD project is to provide fundamental insights on phages and their possible applications in treating staphylococcal biofilm-associated infections. To achieve this aim, the study approach is to investigate multiple features of phage-bacteria interaction, to emphasize strengths and weaknesses of phage therapy, and to look for suitable strategies to overcome phage limitations.