Efficacy of 1950 against etiological agents of community-acquired pneumonia. Bacterial burden in the lungs following treatment with vehicle, ampicillin, or 1950 in mice infected with S. pneumoniae (A), H. influenzae (B), or M. catarrhalis (C). Bacterial burden in the lungs was measured by CFU enumeration. The strains of H. influenzae and M. catarrhalis used in these challenges are resistant to ampicillin. Groups were compared by Mann-Whitney U testing. *, indicates P < 0.05 compared with vehicle control group. Each data point represents titers from one animal. Dotted line indicates the limit of detection.