**2. Materials and Methods**

Ceragenins CSA-13, CSA-131, CSA-44, and CSA-144 were synthesized from a cholic acid scaffolding as previously described [18]. Colistin, chlorhexidine, kanamycin, polymyxin B, erythromycin, tetracycline, vancomycin, and ampicillin were purchased from Sigma–Aldrich (St Louis, MO, USA).
