Fig. 6: Antibiotic class mediated survival difference depends on host TLR9 signaling.

A Schematic representation of peritonitis survival experiments. Tlr9−/− mice were challenged with 10⁹ bacteria via IP injection, given the indicated antibiotic 30 min later, and survival was monitored out to 30 h post infection. B Survival is quantified over 30 h in the indicated number of Tlr9−/− infected mice (displayed as n on the graphs): 16 untreated mice and 18 mice/antibiotic treatment group. Data are pooled across three independent experiments and shown in full. Statistics shown are Kaplan-Meier survival tests comparing survival of cidal treated vs. static treated mice in each genotype. NS is non-significant, and ****P < 0.0001. C Bacterial burdens were quantified by CFU plating from a wash of the peritoneal lavage (PL), and homogenates of the spleen and the left lobe of the liver at 5 min post infection (before antibiotic treatments), and after 4 h after the indicated treatments. Data are pooled from groups of 6 mice (3 male, 3 female) across two independent experiments and shown in full. D Schematic representation of ex vivo cytokine quantification experiment, reproduced for convenience from 1D. cEC1 bacteria were treated until either completely killed (cidal drugs) or growth halted (static drugs), then used in identical quantities to infect mice. Cytokines were quantified 1 and 2 h later. E Plating of ex vivo inocula prior to beginning infections. Six samples were collected and dilution plated from each culture; data shown is representative of three independent experiments. F Tlr9−/− mice were challenged via IP injection with vehicle alone (negative control, black), heat killed bacteria (green), cidal-killed bacteria (ciprofloxacin, blue), and static growth limited bacteria (tetracycline, red). Each mouse received 10⁶ CFU of bacteria in a 100ul  IP injection. Cidal killed bacteria were treated with drug ON to ensure complete killing, whereas static growth halted bacteria were dosed 3 h  prior to infection. Mice were euthanized at 2 h post infection, blood was collected via cardiac puncture, spun down to serum, and promptly frozen. Indicated cytokines were quantified via BD cytokine bead array from serum samples. NS is P > 0.05, *P < 0.05, **P < 0.01, ***P < 0.001, ****P < 0.0001 by two-tailed t test. Representative data from six mice/group is shown from two-four independent experiments. Source data and exact p-values and log rank test values are provided as a Source Data file.