We recently described a family of cationic antimicrobial peptides (cAMPs) selected from a combinatorial library that exhibited potent, broad spectrum activity at neutral pH and low ionic strength.  To further delimit the utility and activity profiles of these peptides, we investigated the effects of solution conditions such as pH and ionic strength on the efficacy of the peptide antimicrobials against a panel of microorganisms.  Peptide minimum sterilizing concentrations (MSC's) varied linearly with pH for each subtype within our family of cAMPs for all organisms tested.  The peptides were much less effective against Gram negative bacteria at high pH, consistent with a decrease in net positive charge on the peptides.  Surprisingly, the opposite pH trend was observed with the Gram positive Staphylococcus aureus.  The novel species specific effects of pH observed here have important implications for the use of cAMPs in a clinical setting.

pH dependant electrostatic interactions of antimicrobial peptides

245th National Meeting (2013)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.