Killing kinetics of RP 59500 and pristinamycin against penicillin-resistant pneumococci.

The killing kinetics of two streptogramins, RP 59500 and pristinamycin against seventeen isolates of penicillin-susceptible and resistant pneumococci were studied. The antibiotics were tested at 1x, 2x and 4x the MIC for each individual isolate. The results showed a very good and rapid bactericidal activity within 1 hour for concentrations equal or greater to the MIC. These antibiotics are very promising agents for the treatment of infections due to multiresistant pneumococci.