[Theoretical research for therapy of infection].

Intractable diseases have been showing a steady increase in recent years. Effective antimicrobial treatment is therefore of the utmost importance. Aminoglycosides and quinolones act in a dose-dependent manner and also exert a postantibiotic effect (PAE), they can therefore be given in large doses at a time with long intervals between administrations. beta-lactams, on the other hand, are characterized by time-dependent antimicrobial action and no PAE towards gram-negative bacteria, so they must be administered at relatively frequent intervals to maintain their concentration at the required level of efficacy.