Combined High Hydrostatic Pressure and Additive Chemical Treatment Enhances Decontamination Efficiency in Bone Tissue Infected with Staphylococcal Biofilms.

Osteomyelitis remains one of the most persistent challenges in orthopedic and trauma surgery, often requiring removal of infected bone tissue segments and leaving critical size defects. Reimplantation of sterilized autologous bone may combine optimal anatomical fit with biological compatibility. This study investigates sodium dodecyl sulfate (SDS) and ethylenediaminetetraacetic acid (EDTA) in combination with high hydrostatic pressure (HHP) as a physicochemical sterilization approach for Staphylococcus aureus and Staphylococcus epidermidis, two of the predominant pathogens associated with osteomyelitis. SDS/EDTA dose determination assays were performed prior to inactivation of different staphylococcal species via HHP with additives. Planktonic S. aureus ATCC 35556 and S. epidermidis ATCC 35984 and ATCC 12228 were exposed to HHP (250 MPa and 350 MPa) in pressure-transmitting media with SDS and EDTA. Furthermore, inactivation of S. aureus and S. epidermidis within biofilms on human trabecular bone cylinders was quantified based on logarithmic reduction factors and evaluated using scanning electron microscopy (SEM). Under HHP, planktonic S. aureus displayed pronounced pressure tolerance, whereas both S. epidermidis strains were fully inactivated at 350 MPa even in 0.9% saline. The addition of SDS/EDTA, which exhibited additive effects (fractional inhibitory concentration (FIC) = 0.7) in planktonic S. aureus, significantly enhanced pressure-induced killing, particularly in biofilms typically limiting sterilization efficiency. SEM revealed substantial membrane deformation and cell wall disruption following the treatment. HHP combined with SDS/EDTA effectively inactivated planktonic and biofilm-associated staphylococci, providing a promising strategy for safe autologous bone reimplantation after infection with the potential to improve clinical outcomes.