Bacterial colonization of polymer brush-coated and pristine silicone rubber implanted in infected pockets in mice

J Antimicrob Chemother. 2008 Dec;62(6):1323-5. doi: 10.1093/jac/dkn395. Epub 2008 Sep 23.

Abstract

Objectives: 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.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Anti-Bacterial Agents / therapeutic use
  • Colony Count, Microbial
  • Mice
  • Mice, Inbred BALB C
  • Polymers*
  • Prostheses and Implants / microbiology*
  • Rifampin / therapeutic use
  • Silicone Elastomers*
  • Staphylococcus aureus / growth & development*
  • Vancomycin / therapeutic use

Substances

  • Anti-Bacterial Agents
  • Polymers
  • Silicone Elastomers
  • Vancomycin
  • Rifampin