ABSTRACT
The objective of any screening program, be it for new pharmacological agents, biocides, or antibiotics, is to examine a large number of candidate substances and rapidly identify those with desired actions which are manifested at sufficiently low concentrations. Methodological approaches to the screening of compounds for utilizable antimicrobial activity are often a compromise between throughput and predictivity. Primary screens of antimicrobial activity may either be conducted in cell-free systems, and investigate activity against known enzymes and processes, or they might utilize intact, whole cells. Cell-free systems have been designed and exploited within antimicrobial screens, which search for activity against particular targets. Whole cells employed as inocula in screening processes must reflect as accurately as possible the physiologies observed in vivo. Suspension test minimal inhibitory concentrations and minimal bactericidal concentrations are wholly inadequate in this respect, unless some attempt is made to utilize media which facilitate slow rates of growth and impose nutrient restriction by iron insufficiency.
