FIG 5.

HM68 has decreased resistance to hydrogen peroxide and acid stress, while HM57 displays deficiency only in human serum resistance. (A) A total of 10⁸ CFU/mL of UPEC were inoculated into LB containing 0.2% H₂O₂ and maintained statically at room temperature. Samples were taken and serially diluted at 0, 15, 30, 45, and 60 min to enumerate the CFU/mL. The means of results of four biological replicates with the associated SEM are shown. (B) From an overnight culture, UPEC isolates were diluted to 10⁸ CFU/mL in LB buffered with MES to pH 7 (blue), 5 (black), or 2.5 (red). Cultures were incubated for 2 h at 37°C with aeration, and the CFU/mL were quantified at both 0 and 2 h to calculate the change in CFU/mL. Error bars indicate the SEM calculated from the mean result of four biological replicates. (C) UPEC isolates were cultured overnight in LB and washed and resuspended in PBS, and then 10⁸ CFU/mL was added to 100% complete human serum. Samples were incubated statically at 37°C for 90 min, and the percent survival (output/input) of samples was enumerated and plotted. Bars represent the mean result of four biological replicates with the SEM indicated by error bars. One-way ANOVA was performed with Dunnett’s multiple-test correction in comparison to CFT073. *, P < 0.05; **, P < 0.01; ***, P < 0.005; ****, P < 0.0001.