ACTIVITIES AGAINST STREPTOCOCCUS-PNEUMONIAE OF AMOXICILLIN AND CEFOTAXIME AT PHYSIOLOGICAL CONCENTRATIONS - IN-VITRO PHARMACODYNAMIC SIMULATION

An in vitro model simulating amoxicillin and cefotaxime concentrations in human serum (after standard doses) aas used to explore the activit ies of these drugs over time against penicillin-susceptible and penici llin-resistant Streptococcus pneumoniae strains. An initial inoculum r eduction percentage of greater than or equal to 90% was obtained with amoxicillin and maintained for 2 to 8 h, regardless of the strain test ed. In contrast, experiments showed that cefotaxime had significantly (P < 0.001) less capability to reduce initial inocula of the penicilli n-resistant pneumococci from 0.5 h on than amoxicillin, despite the sa me in vitro susceptibility to amoxicillin and cefotaxime in both strai ns.