FIG 3.
sfb-negative mice acquire increased resistance to S. aureus pneumonia after colonization with sfb in the GI tract. sfb-negative C57BL/6 mice were gavaged with either PBS (sfb-negative + PBS; n = 5) or sfb-containing stool (sfb-negative + sfb; n = 6) 2 weeks prior to intranasal challenge with MRSA strain LAC at a dose of 5 × 108 CFU (each circle represents an individual animal) (A and B) or 2 × 109 CFU (for a survival experiment) (n = 10 in each group) (C). The data show numbers of bacterial CFU per gram of lung tissue (A) or spleen tissue (B) at 18 h postinfection. (C) Kaplan-Meier survival curves. Symbols represent individual animals, and horizontal bars represent the medians. P values were determined by the Mann-Whitney U test (A and B) or by the log rank test (C).