Polymicrobial periprosthetic joint infection: eradication with different antimicrobials.

Area of Science:

• Biomaterials Science
• Infectious Diseases
• Microbiology

Background:

• Antibiotic-loaded bone cement spacers are used for orthopedic infections but do not guarantee complete eradication.
• Polymicrobial biofilms present a significant challenge due to their complex structure and resistance to antimicrobial agents.

Purpose of the Study:

• To compare the in vitro antimicrobial activity of antibiotic-loaded bone cement with and without additional antimicrobial molecules against polymicrobial biofilms.
• To evaluate the efficacy of different combinations of vancomycin, imipenem, silver nitrate (SN), and xylitol.

Main Methods:

• Methicillin-resistant Staphylococcus aureus (MRSA), Pseudomonas aeruginosa (PA), and Candida albicans (CA) were used to create mono- and polymicrobial biofilms on polyurethane sponges.
• Bone cement was loaded with vancomycin, imipenem, SN, and xylitol in various combinations.
• Antimicrobial activity was assessed in vitro against the developed biofilms.

Main Results:

• The combination of vancomycin + SN + xylitol demonstrated superior activity against MRSA monomicrobial biofilms.
• For polymicrobial biofilms, imipenem + vancomycin + xylitol, imipenem + vancomycin + SN, and imipenem + vancomycin + SN + xylitol were most effective against PA.
• Complete eradication of MRSA was achieved with all tested combinations, but CA eradication remained incomplete.
• The addition of SN and xylitol to the cement formulations improved overall antimicrobial performance.

Conclusions:

• Incorporating silver nitrate and xylitol into antibiotic-loaded bone cement enhances its efficacy against polymicrobial biofilms.
• These adjunctive agents offer a promising strategy to improve the treatment of challenging orthopedic infections.
• Further research is warranted to optimize combinations for complete eradication of all microbial species, including Candida albicans.