Optimization of E. coli Inactivation by Benzalkonium Chloride Reveals the Importance of Quantifying the Inoculum Effect on Chemical Disinfection

“…In our recent study on BAC, we found that d 1 and the fraction of the tolerant subpopulation were concentration dependent, whereas d 2 appeared to be largely independent of the BAC concentration (Nordholt et al 2021). Similar observations were made previously (García and Cabo 2018; Imlay and Linn 1986). Interestingly, the parameters obtained here for the quaternary ammonium compounds BAC and DDAC were quite similar, likely due to a similar mode of action (Table 2).…”

“…A five-fold higher OIT uptake suggests a remarkably higher interaction of this compound with cell membranes of our model organisms, which is consistent with the quick intracellular accumulation of this compound (2-10 min) previously observed in the bacterium Escherichia coli and the yeasts Saccharomyces cerevisiae and Schizosaccharomyces pombe [22,27,28], which may reach peaks of 97% [27]. Efficient accumulations were also observed for BAC in E. coli, and the higher plants Lepidium sativum and Lactuca sativa [25,29], proportional to its availability in the exposure medium.…”

“…Similarly to what was observed by others (Aspridou and Koutsoumanis, 2015), in the experiments conducted to generate the osmotic inactivation rates, number of cells, had no significant effect on the inactivation rates, possibly due to the lack of a cooperative behavior (García and Cabo, 2018). On the other hand, a trial effect was observed, suggesting that such effect could depend on each baseline population history, which determines both regulatory and mutational responses to new environments (Ryall et al, 2012).…”

“…In our recent study on BAC, we found that d 1 and the fraction of the tolerant subpopulation were concentration dependent, whereas d 2 appeared to be largely independent of the BAC concentration (Nordholt et al 2021). Similar observations were made previously (García and Cabo 2018; Imlay and Linn 1986). Interestingly, the parameters obtained here for the quaternary ammonium compounds BAC and DDAC were quite similar, likely due to a similar mode of action (Table 2).…”

“…A five-fold higher OIT uptake suggests a remarkably higher interaction of this compound with cell membranes of our model organisms, which is consistent with the quick intracellular accumulation of this compound (2-10 min) previously observed in the bacterium Escherichia coli and the yeasts Saccharomyces cerevisiae and Schizosaccharomyces pombe [22,27,28], which may reach peaks of 97% [27]. Efficient accumulations were also observed for BAC in E. coli, and the higher plants Lepidium sativum and Lactuca sativa [25,29], proportional to its availability in the exposure medium.…”

“…Similarly to what was observed by others (Aspridou and Koutsoumanis, 2015), in the experiments conducted to generate the osmotic inactivation rates, number of cells, had no significant effect on the inactivation rates, possibly due to the lack of a cooperative behavior (García and Cabo, 2018). On the other hand, a trial effect was observed, suggesting that such effect could depend on each baseline population history, which determines both regulatory and mutational responses to new environments (Ryall et al, 2012).…”

“…In our recent study on BAC, we found that d 1 and the fraction of the tolerant subpopulation were concentration dependent, whereas d 2 appeared to be largely independent of the BAC concentration (Nordholt et al 2021). Similar observations were made previously (García and Cabo 2018; Imlay and Linn 1986). Interestingly, the parameters obtained here for the quaternary ammonium compounds BAC and DDAC were quite similar, likely due to a similar mode of action (Table 2).…”

“…A five-fold higher OIT uptake suggests a remarkably higher interaction of this compound with cell membranes of our model organisms, which is consistent with the quick intracellular accumulation of this compound (2-10 min) previously observed in the bacterium Escherichia coli and the yeasts Saccharomyces cerevisiae and Schizosaccharomyces pombe [22,27,28], which may reach peaks of 97% [27]. Efficient accumulations were also observed for BAC in E. coli, and the higher plants Lepidium sativum and Lactuca sativa [25,29], proportional to its availability in the exposure medium.…”

“…Similarly to what was observed by others (Aspridou and Koutsoumanis, 2015), in the experiments conducted to generate the osmotic inactivation rates, number of cells, had no significant effect on the inactivation rates, possibly due to the lack of a cooperative behavior (García and Cabo, 2018). On the other hand, a trial effect was observed, suggesting that such effect could depend on each baseline population history, which determines both regulatory and mutational responses to new environments (Ryall et al, 2012).…”