Gut microbiota disruption decreases the pulmonary resistance to <i>S</i>. <i>pneumoniae</i>.

Wild-type mice were given broad-spectrum antibiotics or autoclaved saline. Three days after cessation of administration, mice were inoculated intra-nasally with 2.3 × 108 CFU of S. pneumoniae. (A) The survival was observed for 7 days (n = 20 per group). (B) Bacterial load, and (C) TNF-α and (D) IL-1β concentration per mg lung tissue were determined 6 hours and 12 hours after infection (n = 6 per group). CFU, colony-forming units. Data are presented as means ± SD. *P < 0.05, **P < 0.01, ***P < 0.001, analyzed with the log-rank test or unpaired Student’s t test.