Broad-spectrum antibacterial activity by a novel abiogenic peptide mimic

1 Department of Microbiology, University of Massachusetts, Amherst, MA 01003, USA 2 Polymer Science and Engineering Department, University of Massachusetts, Amherst, MA 01003, USA Correspondence Klaus Nüsslein nusslein{at}microbio.umass.edu The human-mediated use and abuse of classical antibiotics has created a strong selective pressure for the rapid evolution of antibiotic resistance. As resistance levels rise, and the efficacy of classical antibiotics wanes, the intensity of the search for alternative antimicrobials has increased. One class of molecules that has attracted much attention is the antimicrobial peptides (AMPs). They exhibit broad-spectrum activity, they are potent and they are widespread as part of the innate defence system of both vertebrates and invertebrates. However, peptides are complex molecules that suffer from proteolytic degradation. The ability to capture the essential properties of antimicrobial peptides in simple easy-to-prepare molecules that are abiotic in origin and non-proteolytic offers many advantages. Mechanistic and structural knowledge of existing AMPs was used to design a novel compound that mimics the biochemical activity of an AMP. This report describes the development and in vitro characterization of a small peptide mimic that exhibited quick-acting and selective antibacterial activity against a broad range of bacteria, including numerous clinically relevant strains, at low MIC values. Abbreviations: AMP, antimicrobial peptide; FA, facially amphiphilic; HC 50 , dose required to lyse 50 % of RBCs; MBC, minimal bactericidal concentration; mPE, meta -phenylene ethynylene; RBC, red blood cell A table showing the results of in vitro tests of antimicrobial activities against a group of selected bacterial species of the peptide mimic mPE after 6 and 20 h, and its selectivity index, is available as supplementary data with the online version of this paper (at http://mic.sgmjournals.org ). Present Address: Clorox Services Company, PO Box 493, Pleasanton, CA 94566, USA. Present Address: Department of Neurology, Beth Israel Deaconess Medical Center, Boston, MA 02215, USA.