the peptides and derivative metapeptides based upon natural antimicrobial peptides have potent and broad spectrum activity against pathogens exhibiting multiple antibiotic resistance . specific peptides can also potentiate the antimicrobial functions of leukocytes , such as neutrophils . in addition , they exhibit lower inherent mammalian cell toxicities than conventional antimicrobial peptides , and overcome problems of toxicity , immunogenicity , and shortness of duration of effectiveness due to biodegradation , retaining activity in plasma and serum . the peptides and derivative metapeptides exhibit rapid microbicidal activities in vitro , can be used to potentiate conventional antimicrobial agents , to potentiate other antimicrobial peptides and are active against many organisms that exhibit resistance to multiple antibiotics currently in existence .