title: Topical colloidal silver as an anti-biofilm agent in a Staphylococcus aureus chronic rhinosinusitis sheep model.
abstract: BACKGROUND
  Treatment of recalcitrant chronic rhinosinusitis (CRS) is a challenge with increasing antibiotic resistance, leading to re-emergence of topical therapies. The aim of this study was to assess safety and efficacy of topical colloidal silver solution for the treatment of Staphylococcus aureus biofilms in a sheep model.
  
  
  METHODS
  In the safety study, normal saline (control) and 30-ppm colloidal silver solution (test) was used to flush the frontal sinuses for 14 days in 8 sheep (4 sheep each). In the efficacy study, following frontal sinus infection with Staphylococcus aureus, sheep were treated with either control saline or topical silver solution of varying concentrations (30 ppm/20 ppm/10 ppm/5 ppm) for 5 days, with 4 sheep in each group. Blood silver level, full blood counts, and biochemical parameters were analyzed in both safety and efficacy studies. Sinus tissue was harvested for histological examination and ciliary structure analysis in safety and for biofilm biomass quantification by fluorescence in situ hybridization (FISH) technique and COMSTAT 2 software in the efficacy study. Results were analyzed using appropriate statistical tests.
  
  
  RESULTS
  Sheep treated with silver showed a significant decrease in biofilm biomass (0.004, 0.004, 0.004, and 0.007, in the 4 silver-treated groups, respectively) compared to saline control (0.175), p < 0.001. Although average blood silver levels were higher in the treated groups compared to controls (p < 0.05), blood counts and biochemical parameters were normal. Histology and ciliary structure analysis did not show any difference between control and treatment groups.
  
  
  CONCLUSIONS
  Topical colloidal silver solution has effective antibiofilm activity in Staphylococcus aureus CRS in a sheep model and appears safe.
authors: Department of Surgery-Otorhinolaryngology, Head and Neck Surgery, University of Adelaide, Adelaide, Australia.
authors: Sukanya
authors: S
authors: Rajiv
authors: Amanda
authors: A
authors: Drilling
authors: Ahmed
authors: A
authors: Bassiouni
authors: Craig
authors: C
authors: James
authors: Sarah
authors: S
authors: Vreugde
authors: Peter-John
authors: PJ
authors: Wormald
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000627:therapeutic use; D018441:Biofilms / Q000187:drug effects*; D004195:Disease Models, Animal; D012220:Rhinitis / Q000188:drug therapy* / Q000382:microbiology; D012756:Sheep; D012834:Silver / Q000627:therapeutic use*; D012852:Sinusitis / Q000188:drug therapy* / Q000382:microbiology; D013203:Staphylococcal Infections / Q000188:drug therapy* / Q000382:microbiology; D013211:Staphylococcus aureus / Q000502:physiology*; D016896:Treatment Outcome
chemical_list: D000900:Anti-Bacterial Agents; C586932:colloidal silver; D012834:Silver
keywords: Staphylococcus aureus; biofilm; chronic rhinosinusitis; colloidal silver; sheep