Fig 4. Assessment of the protective efficacy of SinH-based vaccines reduced the mortality of ExPEC sequence type 131 (ST131) bacteremia.

(A) The vaccination scheme was used in this experiment. BALB/cJ, 6 weeks old, female mice were subcutaneously immunized with SinH-based antigens (SinH-3, SinH-123, N = 12), alum-only (N = 8) or LPS-only (N = 8) and injected with an intraperitoneal (IP) injection of 5 × 10⁷ CFU of ExPEC ST131 strain JJ2050. Mice were monitored twice a day for 10 days, and moribund animals were euthanized/necropsied to determine bacterial levels in the kidneys, spleen, and liver. The schematic diagram was made in BioRender. (B) The survival rate of ST131 ExPEC strain JJ2050 was determined using the Gehan-Breslow-Wilcoxon comparison. (C) Box-and-whisker plots of the JJ2050 bacterial levels (CFU/ml) of the SinH-3 vaccinated group and SinH-123 vaccinated group in combining the counts from all organs (liver, spleen, kidney) at 2 d.p.i and 10 d.p.i. Error bars indicate the median with 95% confidence interval (CI). Significant was determined by the Kruskal-Wallis analysis of variance (ANOVA) with Dunn’s multiple comparisons correction. Symbols represent data of individual mice. One star (*) P < 0.05, two stars (**) P < 0.01, three stars (***) P < 0.001, four stars (****) P < 0.0001. The Box-and-whisker plots and Kaplan Meier survival curves were exported from Graphpad Prism 9 and annotated using BioRender.