Effect of Photodynamic Treatment on Skin Microbiome. Single Center Study
Condition: Postoperative Wound Infection Deep Incisional Surgical Site; Prosthesis and Implants; Surgical Site Infection; Prosthetic Joint Infection
MeSH terms: Infections; Communicable Diseases; Surgical Wound Infection; Wound Infection
Study type: Interventional

Summary: 
      The overarching aim of this research project is to prevent orthopedic implant-associated
      infections. This study aims to investigate if photodynamic therapy has an effect on bacterial
      skin colonization and decrease number of colonizing bacteria associated with sebaceous and
      sweat glands in order to improve skin antisepsis strategies for the prevention of surgical
      site infections.
    

Detailed description: 
      Background. Periprosthetic joint infections are increasing due to our elderly population with
      the need of a joint prosthesis. These infections are difficult to treat, because bacteria are
      able to be sessile (biologically inactive) in the biofilms formed within one day on the
      orthopedic implant surface. Notably, the current available antibiotics do not penetrate the
      biofilm or are not active against the sessile form of bacteria - rifampicin being the only
      antibiotic being active. Therefore, prevention is key. In the current paradigm, bacteria from
      the skin surface or dermis - such as Staphylococcus aureus, coagulase-negative staphylococci,
      or Cutibacterium sp. - contaminate the peri-implant tissue during surgery. In an ongoing
      study with the Orthopedic University Hospital Balgrist (manuscript in preparation), the
      investigators found that the common practice of skin antisepsis is ineffective to eliminate
      skin bacteria before surgery. Strikingly, the skin bacteria hide in sebaceous or sweat
      glands. Photodynamic treatment has recently gained attention in the treatment of acne
      patients, a disease of the pilosebaceous unit, in which also Cutibacterium acnes is
      implicated. The photodynamic treatment works here on the one hand through a long-lasting
      destruction of the sebaceous glands, and on the other hand due to anti-inflammatory and
      antimicrobial effects.

      Hypothesis. The investigators hypothesize that photodynamic treatment improves skin
      antisepsis before surgical implantation of foreign material by reduction of persistent skin
      colonizing bacteria through the destruction of the sebaceous and sweat glands and by its
      bactericidal effects Overall and specific objectives. The overarching aim of this research
      project is to prevent orthopedic implant-associated infections. The specific aim is to
      evaluate the effect of photodynamic treatment on colonizing bacteria immediately after
      surgical skin antisepsis (aim 1) and 3 weeks later (aim 2). In aim 3, the investigators will
      evaluate phylogenetic similarity of same bacterial species before and after photodynamic
      treatment if they persist.

      Methods. The investigators will collect scrapings from the skin surface and quantitatively
      evaluate bacterial species and density before and after photodynamic treatment in combination
      with skin antisepsis of povidone-iodine/alcohol, in aim 1 immediately after skin antisepsis,
      and in aim 2, 21 days after photodynamic treatment. For aim 2, the investigators will
      additionally evaluate changes of sebaceous and sweat glands after photodynamic treatment
      using histopathology. To evaluate phylogenetic similarity of same bacterial species before
      and after photodynamic treatment, the investigators will investigate the core genome using
      whole genome sequencing.

      Relevance and outlook. The current study will investigate if photodynamic treatment is able
      to improve preoperative skin preparation to decrease surgical site infections in hip
      arthroplasty surgery. A decrease of implant-associated infections has multiple benefits,
      among others reduced morbidity, mortality and lower health costs. This study shall provide
      the fundament for a prospective cohort study of patients with planned hip arthroplasty for
      investigating the effect of photodynamic treatment before skin antisepsis.
    

Intervention name(s): Photodynamic treatment
Intervention type(s): Procedure
Intervention description(s): Photosensitiser application, followed by fluorescence photography Photodynamic therapy (PHT) (1x) over 15 minutes
Other intervention name(s): PDT
Intervention model: Single Group Assignment
Intervention model description: The investigator will collect scrapings from the skin surface and quantitatively evaluate bacterial species and density before and after photodynamic treatment in combination with skin antisepsis of povidone-iodine/alcohol, in aim 1 immediately after skin antisepsis, and in aim 2, 21 days after photodynamic treatment. For aim 2, the investigators will additionally evaluate changes of sebaceous and sweat glands after photodynamic treatment using histopathology.
Masking: None (Open Label)
Primary purpose: Other