KILLING ACTIVITY OF CEFPIROME AGAINST PENICILLIN-RESISTANT STREPTOCOCCUS-PNEUMONIAE ISOLATES FROM PATIENTS WITH MENINGITIS IN A PHARMACODYNAMIC MODEL SIMULATING THE CEREBROSPINAL-FLUID CONCENTRATION PROFILE

An in vitro pharmacodynamic model was used to determine the killing ki netics of cefpirome against 20 Streptococcus pneumoniae strains (penic illin G MICs, > 0.125 to 2 mu g/ml) isolated from patients with mening itis. The concentration of cefpirome was adjusted dynamically to simul ate the median concentration profile obtained in the cerebrospinal flu id of adults after the infusion of a single dose of 2 g. The cefpirome MIC at which 90% of isolates are inhibited was 0.5 mu g/ml. Bacterici dal activity was observed at 6 h, with mean killing of 3.51 +/- 0.34 l og(10) CFU/ml for all strains for which the cefpirome MIC was < 0.5 mu g/ml. In contrast, for strains for which the cefpirome MIC was greate r than or equal to 0.5 mu g/ml, killing was significantly less (P < 0. 05), with a mean reduction of only 2.86 +/- 0.57 log(10) CFU/ml.