The antibacterial activity of peptide dendrimers and polymyxin B increases sharply above pH 7.4

Abstract

pH-activity profiling reveals that antimicrobial peptide dendrimers (AMPDs) killKlebsiella pneumoniaeand Methicillin-resistantStaphylococcus aureus(MRSA) at pH = 8.0, against which they are inactive at pH = 7.4, due to stronger electrostatic binding to bacterial cells at higher pH. A similar effect occurs with polymyxin B and might be general for polycationic antimicrobials.