Sub-inhibitory membrane damage undermines Staphylococcus aureus virulence.

We investigated antibacterial properties of a recently described membrane-active lipopeptide, C10OOc12O (decanoyl-ornithyl-ornithyl-dodecanoyl-ornithyl-amide) against Gram-positive bacteria (GPB). Minimal inhibitory concentrations (MICs) and kinetics were compared in culture media and plasma. Chemo-sensitization to antibiotics was determined using the checkerboard assay. Membrane damages were estimated using diverse membrane potential sensitive dyes. ATP levels and relevant enzymes activities were measured using commercial bioassay kits.