Influence of different Salmonella Typhimurium LT2 physiological states (planktonic/biofilm) on the combinatorial effect of Lys68 and outer membrane permeabilizers.

In the planktonic and stationary assay, 50 µL cells resuspended in 10 mM HEPES/NaOH (pH 7.2) to a final 108 CFU/ml were incubated with 25 µL Lys68 (2 µM final concentration) together with 25 µL of citric and malic acid (2 mM and 5 mM final concentrations, respectively) for 2 h. In biofilms assay, cells were washed twice with 200 µL of 10 mM HEPES/NaOH (pH 7.2). Cells were then incubated with 100 µL of Hepes together with 50 µL Lys68 (2 µM final concentration) and 50 µL of citric and malic acid (2 mM and 5 mM final concentrations, respectively) for 2 h. For both experiments, cells incubated with water (instead of citric/malic acid) or PBS (instead of Lys68) were used as negative controls. After incubation CFUs were counted. Averages ± standard deviations are given for n = 4 repeats. Indicated in bold are significant log reduction units observed (≥1 log).Influence of different Salmonella Typhimurium LT2 physiological states (planktonic/biofilm) on the combinatorial effect of Lys68 and outer membrane permeabilizers.