Inactivation of Pseudomonas aeruginosa Mature Biofilm by Monochloramine

Monochloramine has been recognized for its capacity to penetrate biofilms better than other oxidizing agents. In this study, the action of monochloramine on mature biofilms of Pseudomonas aeruginosa developed in vitro on different plumbing materials (polypropylene, polyethylene, electron-ray cross-linked polyethylene reticulate, PVC, copper, stainless steel, and Teflon) was investigated. Its biofilm viability effectiveness was assessed using fluorescence microscopy and confocal microscopy with LIVE/DEAD BacLight. Concentrations of 1 ppm and 2 ppm eradicated the biofilm after 3 h, whereas a lower contact time or a lower concentration (0.5 ppm) had little effect. The results showed that monochloramine was very effective against mature biofilms of P. aeruginosa. Moreover, concentration and contact time greatly affected its activity