Influence of culture medium and inoculum size on susceptibility of Bordetella pertussis to antibacterial agents in vitro.

Experimental examples of different beta-lactam--organism combinations in vitro and in vivo are presented to demonstrate that a rationale for dosage regimens of antibiotics should not be based solely on pharmacokinetic parameters. The time course of the pharmacological response (onset and speed of bacterial killing) and the presence or absence of a postantibiotic effect must also be considered. such pertinent information can be derived from in vitro studies such as time-kill curves and regrowth curves of bacteria obtained at and after short exposure of the target organisms to various concentrations of the drug.