In anti-infective drug development, ex vivo bacterial killing assays utilizing Peripheral Blood Mononuclear Cells (PBMCs) or polymorphonuclear neutrophils (PMNs) are employed to evaluate the functional interplay between a candidate therapeutic and host immune effector mechanisms during pathogen clearance.

Background of Minimum Bactericidal Concentration (MBC)

The Minimum Bactericidal Concentration (MBC) is the lowest concentration of an antimicrobial agent needed to kill at least 99.9% of a specific bacterial population after a defined period of incubation.
While the Minimum Inhibitory Concentration (MIC) is the minimum concentration that prevents visible growth, the MBC is the minimum concentration needed to achieve a lethal effect.

Background of Minimum Inhibitory Concentration (MIC)

The Minimum Inhibitory Concentration (MIC) is the lowest concentration of an antimicrobial that prevents visible growth of a microorganism. 

Determining the MIC for any new antimicrobial is a fundamental step in its development:

Synergy, or checkerboard, assays are standardized in vitro antimicrobial susceptibility assays used to evaluate the pharmacodynamic interaction between two or more therapeutic agents. They are widely employed during drug development to determine whether combining compounds enhances antimicrobial activity compared with each agent administered alone.