A modified chronic infection model for testing treatment of Staphylococcus aureus biofilms on implants

PLoS One. 2014 Oct 3;9(10):e103688. doi: 10.1371/journal.pone.0103688. eCollection 2014.

Abstract

Bacterial biofilms causing implant-associated osteomyelitis is a severe complication with limited antimicrobial therapy options. We designed an animal model, in which implant associated osteomyelitis arise from a Staphylococcus aureus biofilm on a tibia implant. Two bioluminescently engineered (luxA-E transformed), strains of S. aureus were utilized, Xen29 and Xen31. Biofilm formation was assessed with epifluorescence microscopy. Quantitative measurements were performed day 4, 6, 8, 11 and 15 post-surgery. Bacteria were extracted from the biofilm by sonication and the bacterial load quantified by culturing. Biofilm formation was evident from day 6 post-implantation. Mean bacterial load from implants was ∼1×10(4) CFU/implant, while mean bacterial load from infected tibias were 1×10(6) CFU/bone. Bioluminesence imaging revealed decreasing activity throughout the 15-day observation period, with signal intensity for both strains reaching that of the negative control by day 15 while there was no significant reduction in bacterial load. The model is suitable for testing antimicrobial treatment options for implant associated OM, as treatment efficacy on both biofilm and viable counts can be assessed.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Anti-Bacterial Agents / administration & dosage
  • Anti-Bacterial Agents / pharmacology*
  • Bacterial Load
  • Biofilms*
  • Disease Models, Animal
  • Female
  • Mice
  • Osteomyelitis / drug therapy
  • Osteomyelitis / microbiology
  • Prostheses and Implants / adverse effects*
  • Prosthesis-Related Infections / drug therapy*
  • Prosthesis-Related Infections / microbiology*
  • Staphylococcal Infections / drug therapy*
  • Staphylococcal Infections / microbiology*
  • Staphylococcus aureus*
  • Vancomycin / administration & dosage
  • Vancomycin / pharmacology

Substances

  • Anti-Bacterial Agents
  • Vancomycin

Grants and funding

Nis Jørgensen is supported by a PhD grant from the Faculty of Health Science, University of Aarhus, Denmark. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.