Postantibiotic effects of eleven antimicrobials on five bacteria.

Aim: To investigate the postantibiotic effects (PAE) of different classes of antimicrobials against five different types of bacteria. Methods: Minimal inhibitory concentrations (MIC) were determined by twofold macrodilution in broth. The antimicrobial agents were eliminated by washing method after the bacteria were exposed to antimicrobials for 1 h or 2 h. Growth curves were followed by viable counts, and then the PAE were calculated. Results: Macrolides induced PAE of 3.10 h to 4.15 h on S aureus, and 1.85 h to 3.3 h against S pneumoniae, which were longer than PAE induced by other tested antimicrobials (P Conclusion: Different classes of antimicrobials induce different periods of PAE. As an important pharmacodynamic parameter, PAE provide reference data for the determination of the optimal dosing regimen and reasonable use of antimicrobials.