Topical adjuvants incompletely remove adherent Staphylococcus aureus from implant materials

Area of Science:

• Orthopaedic Surgery
• Biomaterials Science
• Microbiology

Background:

• Prosthetic joint infections (PJIs) are challenging due to bacterial biofilms and intracellular bacteria.
• Adjuvant treatments like Betadine, Dakin's solution, and hydrogen peroxide (H2O2) are explored to eradicate PJIs.
• Staphylococcus aureus (S. aureus) is a common pathogen in PJIs, forming resilient biofilms on implant surfaces.

Purpose of the Study:

• To evaluate the in vitro efficacy of chemical adjuvants in reducing S. aureus biofilm on orthopedic implant materials.
• To compare the effectiveness of Betadine, Dakin's solution, H2O2, and chlorine dioxide (ClO2) against S. aureus biofilms.

Main Methods:

• S. aureus biofilms were cultured for 48 hours on titanium, stainless steel, and cobalt chrome discs.
• Biofilms were treated with Betadine, Dakin's solution, H2O2, or 1% ClO2 for five minutes.
• Bacterial colony-forming units per square centimeter (CFU/cm2) were quantified and compared to untreated controls.

Main Results:

• All tested chemical adjuvants significantly reduced S. aureus CFU/cm2 compared to controls (p < 0.05).
• Betadine (98% reduction) and H2O2 (97% reduction) demonstrated the highest efficacy across all metals.
• No significant difference was observed between Betadine and H2O2; both were more effective than Dakin's solution and ClO2.
• Bacterial resistance patterns remained unchanged post-treatment.
• A two-log reduction in CFU/cm2 was achieved, but bacterial counts consistently remained above 10^5 CFU/cm2.

Conclusions:

• Chemical adjuvants like Betadine and H2O2 can significantly reduce S. aureus biofilm in vitro.
• The persistent high bacterial load post-treatment raises questions about the clinical significance for eradicating PJIs.
• Further research into novel techniques is necessary to effectively eliminate biofilms in prosthetic joint infections.