CORRELATION OF IN-VITRO ACTIVITY AND PHARMACOKINETIC PARAMETERS WITH IN-VIVO EFFECT OF AMOXICILLIN, CO-AMOXICLAV AND CEFOTAXIME IN A MURINEMODEL OF PNEUMOCOCCAL PNEUMONIA

In an attempt to determine the susceptibility breakpoints for amoxycil lin, co-amoxiclav and cefotaxime in pneumococcal pneumonia, a neutrope nic mouse model was established and tested with two strains raving dif ferent susceptibility to penicillins and cefotaxime. With a penicillin -sensitive strain (MIC/MBC = 0.01/0.01 mg/L) the minimum dosage tested achieving significant cure was 2 mg/kg for amoxycillin, co-amoxiclav and cefotaxime. For the penicillin-insensitive strain (MIC/MBC = 1/2 m g/L), the minimum dosage tested giving significant cure was 50 mg/kg f or amoxycillin and co-amoxiclav but 100 mg/kg for cefotaxime. Our resu lts support the belief that MICs of amoxycillin, co-amoxiclav and cefo taxime for pneumococcal strains of less than or equal to 0.5 or less t han or equal to 1 mg/L can be considered as clinically relevant suscep tibility breakpoints.