Antimicrobial pharmacodynamics is the relationship between the concentration of an antibiotic and its ability to inhibit vital processes of endo- or ectoparasites and microbial organisms.
[1] The post-antibiotic effect (PAE) is defined as persistent suppression of bacterial growth after a brief exposure (1 or 2 hours) of bacteria to an antibiotic even in the absence of host defense mechanisms.
It has been suggested that an alteration of DNA function is possibly responsible for the post-antibiotic effect following the observation that most inhibitors of protein and nucleic acid synthesis (aminoglycosides, fluoroquinolones, tetracyclines, clindamycin, certain newer macrolides/ketolides, and rifampicin and rifabutin) induce long-term PAE against susceptible bacteria.
[3][5] Proposed mechanisms include (1) slow recovery after reversible nonlethal damage to cell structures; (2) persistence of the drug at a binding site or within the periplasmic space; and (3) the need to synthesize new enzymes before growth can resume.
Antimicrobials with significant PAEs against susceptible gram-negative bacilli are limited to carbapenems and agents that inhibit protein or DNA synthesis.