Proteomic signatures of Staphylococcus aureus biofilm maturation on orthopaedic implants

Implant-associated infections pose a significant clinical challenge in the orthopaedic field, often leading to implant failure and revision surgeries. These infections are hard to treat, particularly due to the formation of bacterial biofilms. Orthopaedic implant surfaces feature varying roughness and compositions to optimise implant osseointegration and performance. Highly polished surfaces are used in articulating areas of high shear force to minimise wear particle formation, while rough or porous surfaces enhance implant and bone fixation. However, increased surface roughness or porosity can also promote bacterial adhesion and biofilm formation, potentially elevating the risk of chronic infections. In this study, an automated single-pot solid-phase enhanced sample preparation protocol (SP3) workflow was developed to investigate the differences in proteomic response of immature and mature S. aureus biofilms on titanium (Ti) surfaces with varying roughness (polished, corundum-blasted), and a plasma-sprayed microporous calcium phosphate coated surface (plasmapore), representing clinically relevant orthopaedic implants. Mature biofilms showed increased proteins related to toxin activity and the tricarboxylic acid (TCA) cycle, while immature biofilms had elevated proteins tied to binding, catalytic activities, and metabolism, suggesting surface topography influences early biofilm formation. This study highlights potential protein targets for novel antimicrobial therapies and suggests testing these as coatings on Ti surfaces, with the proteomics platform serving as a tool to evaluate bacterial and host responses.