CSPP1-E1A inhibits the ability of S. pneumoniae to acquire the rpsL streptomycin resistance gene in mouse peritoneal cavity.

Mice were intraperitoneally infected 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 spleens were harvested between 16–24 hr post-infection, homogenized and plated on THB agar for total bacterial load or THB agar supplemented with streptomycin (100 µg/ml) for rpsL transformants.