Antimicrobial Activity of Peptidomimetics against Multidrug-Resistant Escherichia coli: A Comparative Study of Different Backbones

Novel remedies in the battle against multidrug-resistant bacterial strains are urgently needed, and one obvious approach involves antimicrobial peptides and mimics hereof. The impact of alpha- and beta-peptoid as well as beta(3)-amino acid modifications on the activity profile against beta-lactamase-producing Escherichia coli was assessed by testing an array comprising different types of cationic peptidomimetics obtained by a general monomer-based solid-phase synthesis protocol. Most of the peptidomimetics possessed high to moderate activity toward multidrug-resistant E. coli as opposed to the corresponding inactive peptides. Nevertheless, differences in hemolytic activities indicate that a careful choice of backbone design constitutes a significant parameter in the search for effective cationic antimicrobial peptidomimetics targeting specific bacteria.