Comparison of bactericidal activity after multidose administration of clarithromycin, azithromycin, and cefuroxime axetil against Streptococcus pneumoniae

The objective of this study was to compare the duration of serum bactericid al activity (SBA) for clarithromycin, azithromycin, and cefuroxime axetil i n 12 young healthy volunteers after 5 days of therapy (dosed to steady-stat e) against two strains each of penicillin (PCN)-susceptible, -intermediate, and -resistant Streptococcus pneumoniae. This was a randomized, 3-way cros sover study. All isolates were susceptible to clarithromycin (MICs 0.125 mg /l) and azithromycin (MICs 0.25-0.5 mg/l), while cefuroxime axetil suscepti bilities correlated with PCN. Results showed that SEA was maintained for 10 0% of the dosing interval for clarithromycin and 50-100% for azithromycin r egardless of PCN susceptibility when standard doses were employed. Cefuroxi me axetil was active only against the PCN-susceptible isolate for 50% of th e dosing interval, indicating that it should only be used for PCN-susceptib le S. pneumoniae. (C) 1998 Published by Elsevier Science B.V. and Internati onal Society of Chemotherapy. All rights reserved.