Reduced release of DNA from Streptococcus pneumoniae after treatment with rifampin in comparison to spontaneous growth and ceftriaxone treatment

In order to study the release of DNA from Streptococcus pneumoniae in vitro during spontaneous growth and treatment with ceftriaxone or rifampin, a se miquantitative polymerase chain reaction was used. During spontaneous growt h, high concentrations of bacterial DNA were released. Exposure to 10 mug/m l of ceftriaxone decreased the DNA release, in median, by 19 times (P=0.03 vs. spontaneous growth). Treatment with 10 mug/ml of rifampin led to a redu ction of DNA release, in median, by a factor of 49 (P=0.03 vs. ceftriaxone; six experiments performed on different days).