Assessment of disinfectants cleaning against bacterial biofilm of house hold water tanks.

Abstract The purpose of this study was to compare the efficacy, in terms of bacterial biofilm penetration and killing, of some chemical disinfectants against E. coli and P. aeruginosa. This study was undertaken to examine the efficacy of some disinfectants including sodium hypochlorite, povidine and tryad detergent against E. coli biofilms and the efficacy of sodium hypochlorite and tryad detergents against P. aeruginosa. Two species biofilm of E. coli and P. aeruginosa were grown by flowing a dilute tryptic soy broth medium over an inclined cement, polyethylene, fiberglass and galvanized steel slides, 2.25 x 2.25 cm2 for 15 days. Biofilm formation was evaluated by scanning electron microscopy (SEM) and standard plate counts procedures through selective media for both E. coli and P. aeruginosa. In addition, some disinfectants were selected through disk diffusion susceptibility test. The disinfectants which gave higher zone of inhibitions, were applied to remove of E. coli and P. aeruginosa biofilms from cement, fiberglass, polyethylene and galvanized steel slide surfaces. Results showed that all disinfectants tested gave high inhibition of biofilm adhesion to tank surfaces with some being significant. polyethylene and galvanized steel are strongly recommended as alternative drinking house holds water tanks in Saudi Arabia. The choice of disinfectants or cleaning agents along with optimum concentrations and the time of action is very important when destroying microbes. It is also important that resistance of microbes to some disinfectants and cleaning agents is take into consideration when planning the cleaning process.