Fig 6. K. pneumoniae splenic fitness is maximized by factors relaying resistance to oxidative stress.
(A) Resistance to oxidative stress was measured by incubating K. pneumoniae strains with H2O2. Complementation was performed by comparing strains carrying empty pACYC (ev) to those with pACYC expression of (B) sspA (sspA+pACYCsspA) or (C) pdxA (pdxA+pACYCpdxA). (D-H) In a model of bacteremic pneumonia, mice were infected with 1x106 CFU K. pneumoniae containing a 1:1 mix of KPPR1 and a transposon mutant for (D) dsbA, (E) sspA, or (F) pdxA in Ccr2-/- mice and (G) sspA or (H) ΔpdxA in Cybb-/- mice. For (D-H), the log10 competitive index at 24 hours post infection is displayed for individual mice with bars representing the median and interquartile range. In (A-C), *p<0.05, **p<0.01 by one-way ANOVA with Dunnett’s correction for each strain compared to wild-type, n = 4 in independent trials. Bars represent the mean percent survival for each group. In B-C, lines connect samples from the same replicate. In (D-H), *p<0.05, **p<0.01, ***p<0.001, ****p<0.0001 by one-sample t test with a hypothetical value of zero and ##p<0.01, ###p<0.001 by unpaired t test. For each group, n≥7 mice in two independent infections.