title: Influence of antimicrobial coatings of vacuum-assisted closure dressings on methicillin-resistant Staphylococcus aureus growth kinetics: an in vitro study.
abstract: BACKGROUND
  Silver-containing negative-pressure wound therapy (NPWT) foam dressings should reduce the microbial load of infected surgical sites and thereby promote healing. The effects of silver and an experimental copper coating of NPWT dressings on the growth kinetics of methicillin-resistant Staphylococcus aureus (MRSA) were investigated with a focus on the importance of the initial bacterial load and the incubation time.
  
  
  METHODS
  Commercially available foam samples with and without silver coating were inoculated in vitro with six MRSA suspensions differing in bacterial concentration (1.85×10(3) to 1.85×10(8) colony-forming units per milliliter [CFU/mL]). In a second series, uncoated, silver-containing and experimental copper-coated foam samples were inoculated with one MRSA suspension (1.85×10(6) CFU/mL). The MRSA viable counts in the entrapped fluid were evaluated statistically after 1, 3, 7, and 14 d incubation.
  
  
  RESULTS
  Silver foam samples reduced MRSA counts by two decimal powers compared with the corresponding inocula. With respect to the uncoated samples, silver coating reduced MRSA concentrations by up to 7 logs, which was significant (p≤0.045) for all groups except the one with the highest MRSA concentration. The antibacterial effect of copper became apparent only after 7 d, but thereafter was far more pronounced than the effects of silver (p<0.01 after 14 d).
  
  
  CONCLUSIONS
  Antimicrobial-coated foam dressings showed significant in vitro antibacterial properties and thus could be advantageous in the treatment of MRSA-infected incisions.
authors: 1 Department of Orthopedics, University Medicine Rostock , Rostock, Germany .
authors: Martin
authors: M
authors: Ellenrieder
authors: Sylvio
authors: S
authors: Redanz
authors: Rainer
authors: R
authors: Bader
authors: Wolfram
authors: W
authors: Mittelmeier
authors: Andreas
authors: A
authors: Podbielski
mesh_terms: D000890:Anti-Infective Agents / Q000494:pharmacology*; D001458:Bandages / Q000382:microbiology*; D020099:Coated Materials, Biocompatible / Q000494:pharmacology*; D015169:Colony Count, Microbial; D006801:Humans; D055624:Methicillin-Resistant Staphylococcus aureus / Q000187:drug effects*; D054843:Negative-Pressure Wound Therapy / Q000295:instrumentation*; D016459:Prosthesis-Related Infections / Q000382:microbiology; D012834:Silver / Q000494:pharmacology*; D013203:Staphylococcal Infections / Q000382:microbiology
chemical_list: D000890:Anti-Infective Agents; D020099:Coated Materials, Biocompatible; D012834:Silver