Characteristics of K. pneumoniae strains used in this study. (A) Schematic of the four strains used in this study, with sequence type, O-antigen, and capsule types indicated. (B) Quantification of capsular uronic acids in four K. pneumoniae strains (n = 3). Statistically significant differences between strains were determined by one-way analysis of variance (ANOVA) (overall P < 0.0001) followed by Tukey’s honestly significant difference (HSD) test; **, P < 0.01; ***, P < 0.001; ****, P < 0.0001. (C) Resistance of the four K. pneumoniae strains to killing by pooled human serum (n = 3). Strains were compared by two-factor repeated-measures ANOVA (overall P < 0.0001), and Tukey’s HSD test at t = 180 showed RH201207 to be significantly different from each of the other three strains; ***, P < 0.001.