A simple in vitro system for comparing the bactericidal activity of antibiotics at variable concentrations

: An in vitro device is described that allows the study of bactericidal activity of decreasing antibiotic concentrations. This simple and easily set up device was found to be accurate and reliable. The bactericidal kinetics of three antibacterial compounds (cephalothin, norfloxacin and pristinamycin) on Staphylococcus aureus were compared in a system simulating serum concentration and half-life of each antibacterial compound. The results show the importance of pharmacokinetic parameters on antibacterial activity and their usefulness in new antibiotics evaluation.