title: Octenidine in combination with polymethylmethacrylate: a new option for preventing infection?
abstract: BACKGROUND
  Orthopedic implant infections represent a serious complication for both patient and surgeon. In order to minimize this risk, it has become standard practice in surgery and orthopedics to add antimicrobial substances to the polymethylmethacrylate (PMMA) bone cement. The aim of this study is to find new options for preventing infection by using alternative adjuvants in combination with PMMA. We hypothesized, that Octenidine, after being combined with PMMA, can be released in vitro and an antimicrobial efficacy of discharged Octenidine can be shown.
  
  
  METHODS
  The release of Octenidine from PMMA was assessed in high pressure liquid chromatography of the supernatant. In order to assess the efficacy of Octenidine on Staphylococcus aureus and Pseudomonas aeruginosa in vitro, a nutrient solution for these bacteria was incubated with a defined number of these bacteria (10(6) colony forming units) and cement pellets containing the antiseptic Octenidine for 24 h. After the incubation the number of bacteria in the solution was determined by counting the colony forming units on blood agar plates.
  
  
  RESULTS
  Octenidine was shown to be released in a concentration-dependent manner from PMMA in the elution experiment. The experimental procedure using S. aureus demonstrated a bactericidal effect for bone cement containing Octenidine. For P. aeruginosa, bone cement containing 5-8% Octenidine was associated with tenfold reduction in bacterial count.
  
  
  CONCLUSIONS
  These results suggest that Octenidine is released after combining it with PMMA and reaches working concentrations in vitro. These findings suggest a new and effective alternative for prevention of infection in cemented implants. Further investigations on the biocompatibility of this combination is needed.
authors.affiliation: Department of Orthopedic Surgery, Denver Health Medical Center, 777 Bannock Street, MC 0188, Denver, CO 80204, USA. sebastian.weckbach@dhha.org
authors.forename: Sebastian
authors.initials: S
authors.lastname: Weckbach
authors.forename: Angelika
authors.initials: A
authors.lastname: Möricke
authors.forename: Horst
authors.initials: H
authors.lastname: Braunwarth
authors.forename: Peter
authors.initials: P
authors.lastname: Goroncy-Bermes
authors.forename: Mark
authors.initials: M
authors.lastname: Bischoff
authors.forename: Florian
authors.initials: F
authors.lastname: Gebhard
mesh_terms: D000900:Anti-Bacterial Agents / Q000493:pharmacokinetics / Q000494:pharmacology*; D001843:Bone Cements; D002851:Chromatography, High Pressure Liquid; D015169:Colony Count, Microbial; D006801:Humans; D007097:Imines; D019904:Polymethyl Methacrylate; D016459:Prosthesis-Related Infections / Q000517:prevention & control; D011550:Pseudomonas aeruginosa / Q000187:drug effects* / Q000254:growth & development; D011725:Pyridines / Q000493:pharmacokinetics / Q000494:pharmacology*; D013211:Staphylococcus aureus / Q000187:drug effects* / Q000254:growth & development
chemical_list: D000900:Anti-Bacterial Agents; D001843:Bone Cements; D007097:Imines; D011725:Pyridines; D019904:Polymethyl Methacrylate; C034213:octenidine