Numerous in vitro assays have been devised to identify potential drug leads with potent activities. However, most of these lead candidates fail in the preclinical stage due to lack of adequate in vivo efficacy in animal models. One main reason for such high failure rate is poor pharmacokinetics of the candidate in the host. Herein we describe the use of intravenous continuous infusion to circumvent the inherent poor pharmacokinetics of a given candidate to show in vivo “proof of concept”™ in the early stage of drug discovery (ref. 1). Continuous infusion allows for a putative drug candidate to be maintained at a specified steady-state drug concentration in the host blood and other organs for a prolonged duration, which is not possible by bolus administration. Maintenance of desired steady-state levels of drug gives sufficient time for the drug candidate to confer in vivo efficacy. In an effort to provide greater pharmacokinetic coverage to the lead antimicrobial candidate, platensimycin, we instituted such intravenous continuous infusion with systemic Staphylococcus aureus infection in a murine animal model. This method was successfully used to demonstrate the potent in vivo antibacterial activity of platensimycin against systemic S. aureus) infection.