title: Sustained release varnish containing chlorhexidine for prevention of biofilm formation on urinary catheter surface: in vitro study.
abstract: OBJECTIVE
  Biofilms on the surfaces of urinary catheters are among the pivotal factors for recurrent and persistent infections in urology. Many techniques have been investigated and applied for eradication of these biofilms--but with no full success. The aim of this study was to examine the effect of sustained release medicated varnish, releasing chlorhexidine, on the formation of biofilm on the urinary catheter surface in an in-vitro model.
  
  
  METHODS
  A batch model was used to test the antibacterial/antibiofilm effect of the sustained release varnish: Catheter pieces coated with sustained release varnishes were placed in bacterial growth medium that was infected with Pseudomonas aeruginosa for 96 hours. Various concentrations of chlorhexidine impregnated in the varnish were tested. After the incubation period, the catheter pieces were assessed for biofilm formation by measuring the optical density, colony-forming units, and using confocal laser scanning microscopy, and electron scanning microscopy.
  
  
  RESULTS
  Biofilm growth measurement (colony-forming units [CFU]) on the catheter surface coated with the various concentrations of chlorhexidine in sustained released varnish revealed a 94% reduction with 1% chlorhexidine (P<0.0001) and 43% reduction with 0.1% chlorhexidine (P=0.08) coated varnish in comparison with a positive control or the placebo varnish in preventing biofilm growth of P. aeruginosa. These biologic assays were confirmed using confocal and electron microscopy.
  
  
  CONCLUSIONS
  Of the various tested concentrations of sustained release varnishes, the 1% chlorhexidine concentration has demonstrated the superior antibiofilm effect on urinary catheters with P. aeruginosa. Although similar varnishes are used in dentistry, it needs extended research in animals before applying this technology in human trials.
authors.affiliation: Department of Urology, Hadassah Medical Center, Hadassah-Hebrew University, Ein Kerem, Jerusalem, Israel. nkgudigar@gmail.com
authors.forename: Nandakishore K
authors.initials: NK
authors.lastname: Shapur
authors.forename: Mordechai
authors.initials: M
authors.lastname: Duvdevani
authors.forename: Michael
authors.initials: M
authors.lastname: Friedman
authors.forename: Batya
authors.initials: B
authors.lastname: Zaks
authors.forename: Irit
authors.initials: I
authors.lastname: Gati
authors.forename: Eran
authors.initials: E
authors.lastname: Lavy
authors.forename: Ran
authors.initials: R
authors.lastname: Katz
authors.forename: Ezekiel H
authors.initials: EH
authors.lastname: Landau
authors.forename: Dov
authors.initials: D
authors.lastname: Pode
authors.forename: Ofer N
authors.initials: ON
authors.lastname: Gofrit
authors.forename: Doron
authors.initials: D
authors.lastname: Steinberg
mesh_terms: D018441:Biofilms / Q000187:drug effects* / Q000254:growth & development*; D057785:Catheters / Q000382:microbiology*; D002710:Chlorhexidine / Q000494:pharmacology*; D015169:Colony Count, Microbial; D003692:Delayed-Action Preparations; D006801:Humans; D010150:Paint; D011550:Pseudomonas aeruginosa / Q000187:drug effects* / Q000254:growth & development / Q000502:physiology* / Q000648:ultrastructure; D013499:Surface Properties / Q000187:drug effects; D014546:Urinary Catheterization
chemical_list: D003692:Delayed-Action Preparations; D002710:Chlorhexidine