Pharmacodynamics of moxifloxacin versus vancomycin against biofilms of methicillin-resistant Staphylococcus aureus and epidermidis in an in vitro model.

The aim of this study was to compare the activities of moxifloxacin and vancomycin against methicillin-resistant Staphylococcus aureus (MRSA) and methicillin-resistant Staphylococcus epidermidis (MRSE) biofilms. The study was conducted using a novel in vitro pharmacodynamic model where the biofilms were treated with a simulated clinical dosing of vancomycin 1 g every 12 h or moxifloxacin 400 mg every 24 h. Vancomycin failed to produce a 2 log reduction in the biofilm embedded bacterial count against either of the tested organisms at any time. Moxifloxacin treatment, on the other hand, exhibited a superior anti-biofilm activity and resulted in a 2.5- and 3.7-log reduction in the MRSA and MRSE bacterial bioburdens, respectively, after 24 h of exposure. the results support the implementation of further in vivo and clinical studies aimed at demonstrating the efficacy of moxifloxacin in the treatment of MRSA and MRSE biofilm-associated infections.