Effective Biofilm Eradication on Orthopedic Implants with Methylene Blue Based Antimicrobial Photodynamic Therapy In
Julia Prinz1, Marianne Wink2, Sonja Neuhaus2
1Department of Dermatology, University Hospital Zurich, University of Zurich, 8091 Zurich, Switzerland.
Abstract:
Periprosthetic joint infections (PJI) are difficult to treat due to biofilm formation on implant surfaces, often requiring removal or exchange of prostheses along with long-lasting antibiotic treatment. This in vitro study investigated the effect of methylene blue photodynamic therapy (MB-PDT) on PJI-causing biofilms on different implant materials. MB-PDT (664 nm LED, 15 J/cm2) was tested on different Staphylococcus aureus, Staphylococcus epidermidis, Escherichia coli and Cutibacterium acnes strains in both planktonic form and grown in early and mature biofilms on prosthetic materials (polyethylene, titanium alloys, cobalt-chrome-based alloys, and bone cement). The minimum bactericidal concentration with 100% killing (MBC100%) was determined. Chemical and topographical alterations were investigated on the prosthesis surfaces after MB-PDT. Results showed a MBC100% of 0.5-5 μg/mL for planktonic bacteria and 50-100 μg/mL for bacteria in biofilms-independent of the tested strain, the orthopedic material, or the maturity of the biofilm. Material testing showed no relevant surface modification. MB-PDT effectively eradicated common PJI pathogens on arthroplasty materials without damage to the materials, suggesting that MB-PDT could be used as a novel treatment method, replacing current, more invasive approaches and potentially shortening the antibiotic treatment in PJI. This would improve quality of life and reduce morbidity, mortality, and high health-care costs.
Insights
Methylene blue photodynamic therapy (MB-PDT) effectively eradicated bacteria in biofilms on orthopedic implant materials. This novel approach shows promise for treating periprosthetic joint infections (PJI) without damaging prostheses.
Area of Science:
- Biomedical Engineering
- Infectious Diseases
- Photomedicine
Background:
- Periprosthetic joint infections (PJI) pose significant treatment challenges due to resilient bacterial biofilms on implant surfaces.
- Current PJI management often necessitates invasive surgical procedures and prolonged antibiotic therapies.
Purpose of the Study:
- To evaluate the efficacy of methylene blue photodynamic therapy (MB-PDT) against common PJI pathogens in planktonic and biofilm states.
- To assess the impact of MB-PDT on various orthopedic implant materials.
Main Methods:
- MB-PDT (664 nm LED, 15 J/cm²) was applied to planktonic and biofilm cultures of *Staphylococcus aureus*, *Staphylococcus epidermidis*, *Escherichia coli*, and *Cutibacterium acnes*.
- Biofilms were grown on polyethylene, titanium alloys, cobalt-chrome alloys, and bone cement.
- Minimum bactericidal concentration (MBC100%) was determined, and material surfaces were analyzed for alterations post-treatment.
Main Results:
- MB-PDT demonstrated bactericidal activity with MBC100% ranging from 0.5-5 μg/mL for planktonic bacteria and 50-100 μg/mL for biofilm bacteria.
- Efficacy was consistent across different bacterial strains, implant materials, and biofilm maturity levels.
- No significant chemical or topographical alterations were observed on the prosthesis surfaces after MB-PDT.
Conclusions:
- MB-PDT is a highly effective method for eradicating common PJI pathogens from arthroplasty materials.
- The therapy does not damage implant materials, suggesting its potential as a less invasive alternative to current PJI treatments.
- MB-PDT could reduce the need for extensive surgery and shorten antibiotic courses, improving patient outcomes and lowering healthcare costs.
