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Effect of silver content on the structure and antibacterial activity of silver-doped phosphate-based glasses

By Sabeel P. Valappil, David M. Pickup, Donna L. Carroll, Chris Hope, Jonathan Pratten, Robert J. Newport, Mark E. Smith, Michael Wilson and Jonathan C. Knowles

Abstract

Staphylococcus aureus can cause a range of diseases, such as osteomyellitis, as well as colonize implanted medical devices. In most instances the organism forms biofilms that not only are resistant to the body's defense mechanisms but also display decreased susceptibilities to antibiotics. In the present study, we have examined the effect of increasing silver contents in phosphate-based glasses to prevent the formation of S. aureus biofilms. Silver was found to be an effective bactericidal agent against S. aureus biofilms, and the rate of silver ion release (0.42 to 1.22 mu g.mm(-2).h(-1)) from phosphate-based glass was found to account for the variation in its bactericidal effect. Analysis of biofilms by confocal microscopy indicated that they consisted of an upper layer of viable bacteria together with a layer (similar to 20 mu m) of nonviable cells on the glass surface. Our results showed that regardless of the silver contents in these glasses (10, 15, or 20 mol%) the silver exists in its +1 oxidation state, which is known to be a highly effective bactericidal agent compared to that of silver in other oxidation states (+2 or +3). Analysis of the glasses by P-31 nuclear magnetic resonance imaging and high-energy X-ray diffraction showed that it is the structural rearrangement of the phosphate network that is responsible for the variation in silver ion release and the associated bactericidal effectiveness. Thus, an understanding of the glass structure is important in interpreting the in vitro data and also has important clinical implications for the potential use of the phosphate-based glasses in orthopedic applications to deliver silver ions to combat S. aureus biofilm infections

Topics: Q1
Publisher: American Society for Microbiology
Year: 2007
OAI identifier: oai:kar.kent.ac.uk:8234

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Citations

  1. (2000). A historical review of the use of silver in the treatment of burns. II. Renewed interest for silver.
  2. (2000). A mechanistic study of the antibacterial effect of silver ions on Escherichia coli and Staphylococcus aureus.
  3. An optical microsensor to measure fluorescent light intensity in biofilms.
  4. (2004). Analysis of the effects of chlorhexidine on oral biofilm vitality and structure based on viability profiling and an indicator of membrane integrity.
  5. (2006). Antimicrobial effect of silver-doped phosphate-based glasses.
  6. Antimicrobial effects of metal ions (Ag, Cu2, Zn2) in hydroxyapatite.
  7. (2004). Antimicrobial macroporous gel-glasses: dissolution and cytotoxicity.
  8. (1984). Bacterial adherence and glycocalyx formation in osteomyelitis experimentally induced with Staphylococcus aureus.
  9. (2001). Biofilm exopolysaccharides: a strong and sticky framework.
  10. (2006). Biofilm structure and cell vitality in a laboratory model of subgingival plaque.
  11. (2002). Biofilms: survival mechanisms of clinically relevant microorganisms.
  12. (2002). Broad-spectrum bactericidal activity of Ag2O-doped bioactive glass. Antimicrob. Agents Chemother.
  13. (1998). Burn wound infections: current status.
  14. (2003). Central venous catheterrelated bloodstream infections: pathogenesis factors, new perspectives in prevention and early diagnosis.
  15. (1991). Controlled silver-releasing polymers and their potential for urinary-tract infection control.
  16. (2002). Determining the spatial distribution of viable and nonviable bacteria in hydrated microcosm dental plaques by viability profiling.
  17. (2003). Effect of increasing silver content in phosphate-based glasses on biofilms of Streptococcus sanguis.
  18. (1998). Effects of sucrose and silver on Staphylococcus aureus biofilms.
  19. (1996). Efficacy of disinfectants against biofilm cells of methicillin-resistant Staphylococcus aureus. Microbios 85:223–230.
  20. (1998). Efficacy of silver-coated medical devices.
  21. (1998). Haemocompatiblity of controlled release glass.
  22. (2003). Measuring the thickness of an outer layer of viable bacteria in an oral biofilm by viability mapping.
  23. (2002). Molecular interactions in biofilms.
  24. (2002). Multinuclear solid state NMR of inorganic materials.
  25. (2002). Multiparametric flow cytometry and cell sorting for the assessment of viable, injured, and dead Bifidobacterium cells during bile salt stress.
  26. (2003). Phosphate based glasses for biomedical applications.
  27. (2004). Phosphate glasses for tissue engineering. Part 1. Processing and characterisation of a ternary based P2O5-CaO-Na2O glass system.
  28. (1998). Properties and cytotoxicity of water soluble Na2O-CaO-P2O5 glasses.
  29. Pseudomonas aeruginosa displays multiple phenotypes during development as a biofilm.
  30. (2004). Quorum sensing in Staphylococcus aureus biofilms.
  31. (2005). Role of silver ions in destabilization of intermolecular adhesion forces measured by atomic force microscopy in Staphylococcus epidermidis biofilms. Antimicrob. Agents Chemother.
  32. (1999). Silver ions in the treatment of local infections. MetalBased Drugs 6:311–314.
  33. (2005). Silver valence and local environments in borosilicate and calcium aluminoborate waste glasses as determined from X-ray absorption spectroscopy.
  34. (1999). Silver-containing polymers.
  35. (2002). Staphylococcus and biofilms.
  36. The Calgary biofilm device: new technology for rapid determination of antibiotic susceptibilities of bacterial biofilms.
  37. (2003). The effect of increasing copper content in phosphate-based glasses on biofilms of Streptococcus sanguis.
  38. (1998). The inhibitory effect of Staphylococcus epidermidis slime on the phagocytosis of murine peritoneal macrophages is interferon-independent.
  39. (2000). The structure of simple phosphate glasses.
  40. (1996). The United Kingdom chemical database.

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