Efficacy of disinfectants against biofilm cells of Pseudomonas aeruginosa.

The effect of disinfectants on biofilm cells of Pseudomonas aeruginosa were evaluated. Biofilm cells of P. aeruginosa were eradicated by 0.4 to 0.5% chlorhexidine and 2% glutaral within 1 min, by 0.3% chlorhexidine, 0.5% benzalkonium chloride, 0.1% sodium hypochlorite, and 0.1% titratable I2 providone-iodine within 10 min, and by 0.2% chlorhexidine, 0.1% benzalkonium chloride, and 0.01% sodium hypochlorite within 30 min. However, 0.1% chlorhexidine and 0.1 to 0.5% alkyldiaminoethyl glycine were ineffective for eradication even after 1 h. Eradication of biofilm cells of P. aeruginosa by disinfectants required much longer time than that of planktonic cells in suspensions. The bactericidal effect of disinfectants against biofilm cells was found to be considerably enhanced by increasing the concentrations of the disinfectants.