Eradication of microorganisms embedded in biofilm by an ethanol-based catheter lock solution.
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.
Balestrino
Damien
D
Université Clermont1 UFR Pharmacie, Clermont-Ferrand, France.
Souweine
Bertrand
B
Charbonnel
Nicolas
N
Lautrette
Alexandre
A
Aumeran
Claire
C
Traoré
Ousmane
O
Forestier
Christiane
C
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
D002951:Citrates; C514290:trisodium citrate; D000431:Ethanol