title: Eradication of microorganisms embedded in biofilm by an ethanol-based catheter lock solution.
abstract: BACKGROUND
  Interdialytic locking of catheters with antimicrobial agents is frequently used for preventing catheter-related infections, often associated with biofilm formation. We determined the bactericidal effect of 60% ethanol (ETOH) versus a 46.7% trisodium citrate (TSC) solution on biofilm embedded in silicone catheters.
  
  
  METHODS
  Four- and 24-h biofilms of Staphylococcus aureus, S. epidermidis, Pseudomonas aeruginosa, Klebsiella pneumoniae and Candida albicans established in a microfermentor were exposed to ETOH and TSC for up to 24 h and the number of remaining viable microorganisms was determined.
  
  
  RESULTS
  ETOH 60% was significantly more effective than 46.7% TSC in rapidly eradicating sessile cells from all microorganisms tested. A 20-min ETOH 60% treatment completely eradicated the Gram-negative bacilli and C. albicans biofilms, which initially contained up to 10(8) and 10(5) cells, respectively. Gram-positive cocci biofilms only showed a significant 2.6-4.3 log reduction in the initial viable counts after 20 min of ETOH 60% treatment, with eradication occurring after 30 min. Confocal laser scanning microscopy observation of ETOH-treated biofilm showed sparse cells with respiratory activity. TSC 46.7% eradicated none of the tested microorganisms. In contrast, ETOH 60% totally eradicated planktonic cells, whereas TSC had significant bactericidal activity against K. pneumoniae, P. aeruginosa and C. albicans after 20 min, 1 and 24 h, respectively, but none on the Staphylococcus species.
  
  
  CONCLUSIONS
  This in vitro study demonstrates the superior antimicrobial activity of ETOH 60% in contrast to TSC 46.7% in eradicating biofilm formed on a silicon catheter. Hence, ethanol-based solution shows promise as a catheter lock solution.
authors.affiliation: Université Clermont1 UFR Pharmacie, Clermont-Ferrand, France.
authors.forename: Damien
authors.initials: D
authors.lastname: Balestrino
authors.forename: Bertrand
authors.initials: B
authors.lastname: Souweine
authors.forename: Nicolas
authors.initials: N
authors.lastname: Charbonnel
authors.forename: Alexandre
authors.initials: A
authors.lastname: Lautrette
authors.forename: Claire
authors.initials: C
authors.lastname: Aumeran
authors.forename: Ousmane
authors.initials: O
authors.lastname: Traoré
authors.forename: Christiane
authors.initials: C
authors.lastname: Forestier
mesh_terms: D018441:Biofilms / Q000187:drug effects*; D002176:Candida albicans / Q000187:drug effects; D002404:Catheterization; D002951:Citrates / Q000494:pharmacology*; D004866:Equipment Contamination; D000431:Ethanol / Q000493:pharmacokinetics*; D007711:Klebsiella pneumoniae / Q000187:drug effects; D011550:Pseudomonas aeruginosa / Q000187:drug effects; D013211:Staphylococcus aureus / Q000187:drug effects; D013212:Staphylococcus epidermidis / Q000187:drug effects; D013997:Time Factors
chemical_list: D002951:Citrates; C514290:trisodium citrate; D000431:Ethanol