Quantification of methicillin-resistant S. aureus (MRSA) biofilm formation on orthopedic implants using bioluminescence imaging

Methicillin-resistant S. aureus (MRSA) bacteria commonly found on orthopaedic implants, form treatment resistant biofilms that are difficult to manage. Creating new imaging modalities that allow us to understand biofilm development and accurately indicate the efficacy of treatments will greatly aid research in biofilm infection treatment methods. In this in vitro study, we determined the correlation between the number of MRSA CFUs and the radiance of MRSA aliquots with bioluminescent plasmids in the resolution volume of the Perkin Elmer's IVIS Spectrum imaging system at specific imaging depths. We standardized MRSA bioluminescence curves for planktonic and biofilm-associated MRSA grown on titanium and stainless-steel orthopaedic hardware. The ability to relate measured radiance to the biofilm bioburden on a metal surface provides a critical tool for our ongoing pre-clinical studies identifying and treating biofilm-forming infections in contaminated high-energy fracture (rats) and contaminated osseointegration after amputation (rabbits).