title: Bacterial colonization of polymer brush-coated and pristine silicone rubber implanted in infected pockets in mice.
abstract: OBJECTIVE
  Curing biomaterial-associated infection (BAI) frequently includes antibiotic treatment, implant removal and re-implantation. However, revision implants are at a greater risk of infection as they may attract bacteria from their infected surroundings. Polymer brush-coatings attract low numbers of bacteria, but the virtue of polymer brush-coatings in vivo has seldom been investigated. Here, we determine the possible benefits of polymer brush-coated versus pristine silicone rubber in revision surgery, using a murine model.
  
  
  METHODS
  BAI was induced in 26 mice by subcutaneous implantation of silicone rubber discs with a biofilm of Staphylococcus aureus Xen29. During the development of BAI, half of the mice received rifampicin/vancomycin treatment. After 5 days, the infected discs were removed from all mice, and either a polymer brush-coated or pristine silicone rubber disc was re-implanted. Revision discs were explanted after 5 days, and the number of cfu cultured from the discs and the surrounding tissue was determined.
  
  
  RESULTS
  None of the polymer brush-coated discs after antibiotic treatment appeared colonized by staphylococci, whereas 83% of the pristine silicone rubber discs were re-infected. Polymer brush-coated discs also showed reduced colonization rates in the absence of antibiotic treatment when compared with pristine silicone rubber discs. Tissue surrounding the discs was culture-positive in all cases.
  
  
  CONCLUSIONS
  Polymer brush-coatings are less prone to re-infection than pristine silicone rubber when used in revision surgery, i.e. when implanted in a subcutaneous pocket infected by a staphylococcal BAI. Antibiotic pre-treatment during the development of BAI hardly had any effect in preventing the colonization of pristine silicone rubber.
authors.affiliation: Department of Biomedical Engineering, University Medical Center Groningen and University of Groningen, Antonius Deusinglaan 1, 9713 AV Groningen, The Netherlands.
authors.forename: M Reza
authors.initials: MR
authors.lastname: Nejadnik
authors.forename: Anton F
authors.initials: AF
authors.lastname: Engelsman
authors.forename: Isabel C
authors.initials: IC
authors.lastname: Saldarriaga Fernandez
authors.forename: Henk J
authors.initials: HJ
authors.lastname: Busscher
authors.forename: Willem
authors.initials: W
authors.lastname: Norde
authors.forename: Henny C
authors.initials: HC
authors.lastname: van der Mei
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000627:therapeutic use; D015169:Colony Count, Microbial; D051379:Mice; D008807:Mice, Inbred BALB C; D011108:Polymers; D019736:Prostheses and Implants / Q000382:microbiology*; D012293:Rifampin / Q000627:therapeutic use; D012826:Silicone Elastomers; D013211:Staphylococcus aureus / Q000254:growth & development*; D014640:Vancomycin / Q000627:therapeutic use
chemical_list: D000900:Anti-Bacterial Agents; D011108:Polymers; D012826:Silicone Elastomers; D014640:Vancomycin; D012293:Rifampin