Effects of prior colonisation on progression of subsequent S. pneumoniae pneumonia.
(A) Kaplan-Meier survival curves of previously colonised or control CBA/Ca mice following pneumonia challenge with 107 cfu D39 S. pneumoniae in 50 µl PBS on day 28 (n = 18 or 19). (B–D) Bacterial cfu in BALF, lung or blood of colonised or control mice at (B) 4 h, (C) 9 h or (D) 18 h following pneumonia challenge. Each symbol represents results for an individual mouse and bars the median for each group. The dotted line is the limit of detection. Significance of the difference in bacterial numbers recovered from lungs of colonised and control mice was assessed by Mann-Whitney U-test. Significance of differences in presence or absence of bacteraemia was assessed by Fisher exact test. Data at 18 h are pooled from two experiments with similar results.
