Cardiolipin (CL) is a tetra-acylated phospholipid with two (at neutral pH negatively chrged) phosphate groups and four acyl tails, generally 16-18 carbons in length and possibly saturated, mono-unsaturated, cyclopropanated, or branched (either in the iso-anteiso-conformation) . CL's characteristic inverted cone shape and the associated negative spontaneous curvature leads to its accumulation in highly curved membrane domains, such as the septal and polar ones . This accumulation of PE and CL in highly curved regions is common to both Gram-positive and Gramnegative cell membranes. The level of CL is higher in species like Staphylococcus aureus, especially in the L-form (lacking cell wall), suggesting that CL may interact with cations to stabilize the membrane when the cell is more vulnerable . Such membrane stabilizing role may have important consequences for AMPs susceptibility.