Survival rate and immune response in <i>K. pneumoniae</i>-inoculated mice.

<p><b><i>A</i></b> and <b><i>B</i></b>, Eight mice per group were infected with the wild-type and the <i>wbbO</i> mutant strains at an intraperitoneal (IP) dose of 1×10<sup>3</sup> CFU/animal or an intragastrical (IG) dose of 1×10<sup>6</sup> CFU/animal. Survival of mice was monitored for 4 (IP) or 6 (IG) weeks. ▪, NTUH-K2044; □, K2044 <i>wbbO</i>; ▴, NTUH-A4528; ▵, A4528 <i>wbbO</i> mutant (K2044 <i>wbbO</i> vs. parent, <i>P</i> = 0.0002 (IP) and <i>P</i> = 0.4417 (IG); A4528 <i>wbbO</i> vs. parent, <i>P</i><0.0001 (IP) and <i>P</i> = 0.0129 (IG); log-rank test). <b><i>C</i></b> to <b><i>F</i></b>, Equivalent doses (1×10<sup>3</sup> CFU) of the wild-type, the <i>wbbO</i> mutant, and the <i>wbbO</i> mutant with the <i>wb</i> cluster complementation were inoculated into mice (4 mice per group) by IP injection. Surviving animals were sacrificed at 24 hours after challenge. Bacterial loads were measured in the blood (<b><i>C</i></b>), liver, and spleen (<b><i>D</i></b>); TNF-α (<b><i>E</i></b>) and IL-6 (<b><i>F</i></b>) levels were measured in the serum. Log<sub>10</sub> CFU was standardized per 0.1 gram wet organ weight. IL-6 and TNF-alpha levels were measured by ELISA. Data are presented as means ± standard deviations. ND, not detected. <sup>**</sup><i>P</i><0.01 and <sup>*</sup><i>P</i><0.05 by Student's <i>t</i> test (<i>wbbO</i> mutant group vs. wild-type group or the <i>wbbO</i> mutant with the <i>wb</i> cluster complementation group).</p>