Bioactive Glass S53P4 cream kills ESKAPE panel multidrug resistant pathogens and Staphylococcus aureus biofilms

Orthopedic implant-associated infections, predominantly caused by Staphylococcus aureus, pose significant challenges due to biofilm formation and antibiotic resistance. Bioactive Glass (BAG) S53P4 is a unique material with antimicrobial and bone regenerative properties. We aimed to characterize a novel BAG S53P4 cream, consisting of BAG powder and a binder, for its capacity to kill S. aureus in suspension and biofilms in absence or presence of titanium implant material. Since the BAG antimicrobial activity depends on ions eluted, we also analyzed the eluates of the cream and of powder and binder. The BAG cream and BAG powder applied to titanium implant material, as well as their respective eluates eradicated planktonic S. aureus. Elemental release from BAG cream and powder showed time-dependent shifts in levels of silicona, sodium, calcium and phosphorous together with stable alkaline pH levels, reflecting continuous ion release from the glass network and concurrent precipitation of calcium phosphate and silica phases. BAG cream and powder eluates collected as early as at 2 hours were highly effective against the bacterial species S. aureus, the ESKAPE panel of multidrug resistant pathogens, colistin-resistant Escherichia coli and Cutibacterium acnes, and against the fungi Candidozyma auris and Candida albicans. The eluates displayed time-dependent bactericidal activity with significant bacterial killing starting already at 30 minutes and increasing with longer exposure times. Moreover, significant reduction in S. aureus biofilm was observed with the cream and powder eluates. BAG cream was easy to apply to the bone defect of a cadaver mouse using a syringe and it effectively prevented S. aureus growth. These findings show the potential of BAG cream as an innovative application form of BAG S53P4 offering a promising approach against orthopedic implant-associated infections.