CSPP1-E1A inhibits the ability of <i>S. pneumoniae</i> to acquire the <i>rpsL</i> streptomycin resistance gene in mouse lungs during acute pneumonia.

Mice (n = 5) were intranasally inoculated with D39 (3×107, 50 µl volume) supplemented with 100 ng CSP1 and 10 µg of rpsL gene DNA, or D39 supplemented with a mixture 100 ng CSP1, 800 ng CSP1-E1A and 10 µg of rpsL gene DNA in THB. Mouse lungs were harvested 6 hr post-inoculation, homogenized and plated on THB agar for total bacterial load or THB agar supplemented with streptomycin (100 µg/ml) for rpsL transformants.