Figure 2.

The acid determinant nlpD is involved in the pathogenicity of Cronobacter sakazakii.

(A) Survival of rat pups during the 120-hour period following oral infection with various bacterial strains. Combined data from three independent experiments are shown (log-rank test; ***, P < 0.001). (B–D) Colony-forming units (CFU) present in the blood, liver, and spleen of infected rats at 24 hours post-infection. Blood was collected from the facial vein, and the liver and spleen were harvested and homogenized in ice-cold PBS for use in colony enumeration. (E) Histopathologic examination of intestinal tissues of uninfected, WT-infected, and ΔnlpD-infected rats. Scale bars, 100 μm. (F) Intestinal sections obtained at 24 hours post-infection were graded as grade 0 (normal) to grade 4 (severe) by a pathologist blinded to the groups according to morphological changes (n = 4). Salmonella enterica serovar Typhimurium and E. coli DH5α serve as positive and negative controls, respectively.