Breakpoints for extended-spectrum beta-lactamase-producing Enterobacteriacae: pharmacokinetic/pharmacodynamic considerations.

An understanding of antibacterial pharmacokinetics and pharmacodynamics is central to setting clinical breakpoints. It is important to understand any impact that a resistance mechanism may have on these basic drug properties. With extended-spectrum beta-lactamase (ESBL)-producing strains of Enterobacteriacae, it is known that MIC, and hence T>MIC, for beta-lactams predicts outcome. Therefore, pharmacodynamic modelling can be used to set breakpoints for ESBL-producing bacteria with beta-lactams.