Inactivation Kinetics of Various Chemical Disinfectants on Aeromonas hydrophila Planktonic Cells and Biofilms

Abstract

The present article focuses on the inactivation kinetics of various disinfectants including ethanol, sodium hypochlorite, hydrogen peroxide, peracetic acid, and benzalkonium chloride against Aeromonas hydrophila biofilms and planktonic cells. Efficacy was determined by viable plate count and compared using a modified Weibull model. The removal of the biofilms matrix was determined by the crystal violet assay and was confirmed by field-emission scanning electron microscope. The results revealed that all the experimental data and calculated Weibull α (scale) and β (shape) parameters had a good fit, as the R(2) values were between 0.88 and 0.99. Biofilms are more resistant to disinfectants than planktonic cells. Ethanol (70%) was the most effective in killing cells in the biofilms and significantly reduced (p<0.05) the biofilms matrix. The Weibull parameter b-value correlated (R(2)=0.6835) with the biofilms matrix removal. The present findings deduce that the Weibull model is suitable to determine biofilms matrix reduction as well as the effectiveness of chemical disinfectants on biofilms. The study showed that the Weibull model could successfully be used on food and food contact surfaces to determine the exact contact time for killing biofilms-forming foodborne pathogens.

The Social Life of Aeromonas through Biofilm and Quorum Sensing Systems

“…Aeromonads within a biofilm are more resistant to disinfectants than planktonic cells, as shown for A. hydrophila strains (Jahid and Ha, 2014). Aeromonads have thus been recovered from biofilm in drinking-water distribution systems (Chauret et al, 2001; September et al, 2007), even when water supply is chlorinated (Fernández et al, 2000).…”

Response of Formed‐Biofilm of Enterobacter cloacae, Klebsiella oxytoca, and Citrobacter freundii to Chlorite‐Based Disinfectants

“…In fact, the disinfection by SH is greatly dependent on the strains of bacteria. Jahid and Ha () reported reductions of 6.5 and 6.7 log CFU/cm 2 after a 30‐min treatment with SH of Aeromonas hydrophila planktonic cells, whereas similar effects have been observed with 2000 and 4000 mg/L for biofilm cells, and in a recent study, SH was not very effective in killing biofilms (Pagedar & Singh, ). The presence of organic materials can also decrease the bactericidal effect of disinfectants along with a decrease in the ACC (Fukuzaki, ).…”

Aeromonas biofilm on stainless steel: efficiency of commonly used disinfectants

“…Sodium hypochlorite solutions have been widely used for hard‐surface disinfection, even in our homes, with known efficiency, while amphoteric surfactants, although efficient in many cases, are also know to induce resistance (McDonnell & Russel, ). Jahid & Ha () demonstrated that sodium hypochlorite was more efficient in removing aeromonads biofilm from polystyrene, as well as changing cell morphology, when compared with chemical disinfectants such as ethanol, hydrogen peroxide and benzalkonium chloride. Furthermore, Wirtanen et al .…”

“…Sodium hypochlorite solutions have been widely used for hard-surface disinfection, even in our homes, with known efficiency, while amphoteric surfactants, although efficient in many cases, are also know to induce resistance (McDonnell & Russel, 1999). Jahid & Ha (2014) demonstrated that sodium hypochlorite was more efficient in removing aeromonads biofilm from polystyrene, as well as changing cell morphology, when compared with chemical disinfectants such as ethanol, hydrogen peroxide and benzalkonium chloride. Furthermore, Wirtanen et al (2001) demonstrated that commercial disinfectants based on amphoteric surfactants were the least effective in removing biofilms formed by several foodborne pathogenic micro-organisms (Pseudomonas fragi, Enterobacter sp., L. monocytogenes and Bacillus subtilis) on stainless steel for 2 days at 30°C, when compared to sodium hypochlorite-and sodium hydroxide-based disinfectants, among others.…”