Evaluation of Chemical Disinfectants Efficacy against Escherichia coli Biofilm Developed at 37°C on Glass and Stainless steel
Keywords:
Biofilm, E. coli, Colony forming unit per mill (CFU/ml), Disinfectants, Log reduction (LR).Abstract
This work aimed at studying biofilm development on glass and stainless steel (SS) at various incubation periods and assessing the action of hydrogen peroxide (HP), para acetic acid (PAA), sodium hypochlorite (SH), and mixture of PAA and SH against the biofilm. A 200 μl of 108 CFU/ml suspension of E. coli ATCC 29922 was inoculated on the coupons inside petri dishes containing 20 ml of Tryptic Soy Broth, incubated at 37°C for 24, 48, 72 and 168 hours. At each hour of incubation, viable cells developed were vortexed and quantified by agar plating. The action of the disinfectants against the biofilm was tested after 168 hours of incubation. The results showed that E. coli developed highest biofilm on glass than on SS coupons. After disinfection treatment, HP had the highest bactericidal effect with LR value of 1.29 on glass while SH had the least bactericidal effect with LR value of 0.81 on glass. It can be concluded from this work that HP can be a good disinfectant against E. coli biofilm than PAA and SH.
