title: Could liposomal amphotericin B (L-AMB) lock solutions be useful to inhibit Candida spp. biofilms on silicone biomaterials?
abstract: OBJECTIVE
  Candida infections associated with catheters remain difficult to manage. Antifungal lock strategies could be a therapeutic option when the device is difficult to remove or in combination with systemic treatment to increase efficacy. This study deals with the antibiofilm potential of liposomal amphotericin B (L-AMB) used as a lock solution to inhibit Candida albicans, Candida glabrata and Candida parapsilosis biofilms in vitro.
  
  
  METHODS
  Biofilms aged 12 h and 5 days were formed on silicone catheters. L-AMB (200 or 1000 mg/L) was added to biofilms and catheters were incubated for 4, 12 or 24 h at 37°C. L-AMB was then removed by washing. The metabolic activity of yeasts was assessed by the XTT method up to 48 h after the end of the locks to evaluate the persistence of the antibiofilm activity. Controls without antifungal were used as references to calculate the inhibition percentages induced by L-AMB lock solutions.
  
  
  RESULTS
  L-AMB (200 and 1000 mg/L) inhibited, for up to 48 h, C. albicans and C. glabrata biofilms by >70%, regardless of the lock duration. The activity of L-AMB (200 mg/L) against C. parapsilosis mature biofilms was lower and less sustained, especially for 4 h locks.
  
  
  CONCLUSIONS
  L-AMB (1000 mg/L) lock solutions strongly inhibited Candida spp. in young and mature biofilms for up to 48 h after the end of the lock. However, overall eradication of the biofilm was not obtained using 1000 mg/L L-AMB as a single lock. These results suggest the usefulness of systemic treatment combined with an L-AMB lock to control Candida spp. biofilms associated with catheters.
authors.affiliation: UMR CNRS 6008,  Université de Poitiers, 6 rue de la Milètrie, BP 199, 86034 Poitiers cedex,  France.
authors.forename: Delphine
authors.initials: D
authors.lastname: Toulet
authors.forename: Cécile
authors.initials: C
authors.lastname: Debarre
authors.forename: Christine
authors.initials: C
authors.lastname: Imbert
mesh_terms: D000666:Amphotericin B / Q000494:pharmacology*; D000935:Antifungal Agents / Q000008:administration & dosage; D001672:Biocompatible Materials; D018441:Biofilms / Q000254:growth & development*; D002175:Candida / Q000187:drug effects / Q000254:growth & development* / Q000378:metabolism; D002177:Candidiasis / Q000382:microbiology / Q000517:prevention & control*; D055499:Catheter-Related Infections / Q000382:microbiology / Q000517:prevention & control*; D057785:Catheters / Q000382:microbiology*; D004203:Disinfection / Q000379:methods*; D006801:Humans; D050296:Microbial Viability / Q000187:drug effects; D012828:Silicones; D013194:Staining and Labeling / Q000379:methods; D013778:Tetrazolium Salts / Q000378:metabolism
chemical_list: D000935:Antifungal Agents; D001672:Biocompatible Materials; D012828:Silicones; D013778:Tetrazolium Salts; C068538:liposomal amphotericin B; C059087:2,3-bis(2-methoxy-4-nitro-5-sulfophenyl)-5-((phenylamino)carbonyl)-2H-tetrazolium hydroxide; D000666:Amphotericin B