Effective Biofilm Eradication on Orthopedic Implants with Methylene Blue Based Antimicrobial Photodynamic Therapy In Vitro

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

Effective Biofilm Eradication on Orthopedic Implants with Methylene Blue Based Antimicrobial Photodynamic Therapy In Vitro

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

Bildung und subjektives Wohlbefinden im Zeitverlauf, 1984–2002. Eine Mehrebenenanalyse

Diese Analyse des subjektiven Wohlbefindens verfolgt zwei Ziele. Zum einen wird die Entwicklung des subjektiven Wohlbefindens über die Periode zwischen 1984 und 2002 untersucht. Dabei werden Alters-, Perioden- und Kohorteneffekte simultan betrachtet. Als soziale Mechanismen hinter den Wandlungsprozessen, das heißt als Prädiktoren für das subjektive Wohlbefinden und die Variation im Zeitverlauf, werden Bildung und Bildungsexpansion thematisiert und in die Analysemodelle eingeführt. Um die Lebenszufriedenheit unabhängig von gesundheitlichen Aspekten zu untersuchen, wird die Gesundheitszufriedenheit kontrolliert. Methodisch folgt der Beitrag einem Mehrebenenansatz. Zur Datenanalyse werden Hierarchisch Lineare Modelle (HLM) herangezogen. Detailliert wird auf die benötigte Datenstruktur, die Anwendbarkeit und die Parameter-Schätzungen von HLM eingegangen. Die Datengrundlage bildet das Sozio-Ökonomische Panel (SOEP), wobei nur die Teil-Stichprobe der Westdeutschen in die Analyse einbezogen wird. In den Resultaten zeigen sich – neben einem starken Einfluss der Gesundheitszufriedenheit – u. a. robuste Bildungseffekte, ein substanzieller Alterseffekt und ein schwacher negativer Kohorteneffekt auf die Lebenszufriedenheit