The research article "The antibacterial activity of peptide dendrimers and polymyxin B increases sharply above pH 7.4" was recently published in Chemical Communications.
pH-activity profiling reveals that antimicrobial peptide dendrimers (AMPDs) kill Klebsiella pneumoniae and Methicillin-resistant Staphylococcus 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.

Author(s): Xingguang Cai, Sacha Javor, Bee Ha Gan, Thilo Kohler and Jean-Louis Reymond