BACTERIOPHAGES IN CONTACT WITH GRANULES AND EXPERIMENTAL SCAFFOLDS OF BAG S53P4 ENHANCE THE ANTIBACTERIAL EFFECT AGAINST STAPHYLOCOCCUS AUREUS IN VITRO

Aim Bioactive glass (BAG), S53P4 is a bone substitute with documented antibacterial properties, attributed to a pH-altering effect and osmotic pressure in the vicinity of the glass. Clinically, granules of BAG S53P4 are used in various applications in the treatment of bone infections; in osteomyelitis, frontal sinus -, oral and maxillofacial -, mastoid - and diabetic foot surgery. The increasing antimicrobial resistance, today considered a global treat, has subsequently increased the interest in bacteriophages in the treatment of infections. The aim of the study was to test different forms of BAG S53P4 against Staph aureus in combination with bacteriophages to evaluate the combined effect of BAG S53P4 and the bacteriophages in-vitro . Method First the bacteriophages were tested for tolerance to an increase in pH 2-12, due to the known surface reactions in solution of BAG S53P4, which after they were tested together with powder, granules and experimental scaffolds of BAG S53P4. Finally, bacteriophages, BAG S53P4 and the different forms of BAG S53P4 were tested together with Staph aureus . Results Bacteriophages tolerated an increase in pH in solution well both from the granules and the scaffolds, but not from the powder. BAG S53P4 powder alone killed most of the bacteria, followed by the granules and scaffolds. For granules, a slight difference in antibacterial efficacy was observed in favor of the combination of BAG S53P4 and bacteriophages, which was even more clearly observable for bacteriophages and scaffolds. Conclusions In an experimental setting including powder, granules and experimental scaffolds of BAG S53P4 and Staph. aureus combined with bacteriophages, an increased antibacterial effect was observed, for granules and scaffolds making the combination of bacteriophages and BAG S53P4 a promising tool in the treatment of challenging bone infections.