The continuous use of antibiotics has resulted in multi-resistant bacterial strains  all over the world and as expected,  hospitals have become breeding grounds for human-associated micro organisms. Nonetheless, the same time-bomb effect is slowly developing with animal-associated pathogens  in commercially driven activities, such as aquaculture and confined poultry breeding,  where the indiscriminate use of antibiotics is perceivedasessential for industries survival. Consequently, there is an urgent need to search for alternatives to synthetic antibiotics. The discovery of two classes of  antimicrobial peptides, non-ribosomally synthesized (Hancock and Chapple, 1999)- present in bacteria - lower eukaryotes and plants -  and  ribosomally-synthesized peptides, of wider distribution , provided a new therapeutic strategy to fight micro organisms. Recent studies show that several cationic and non-cationic peptides  expressed in many vertebrate, invertebrate and bacterial species  act  synergistically to improve immune responses.

The knowledge acquired in the past two decades and the discovery of new groups of antimicrobial peptides make natural antibiotics the basic element of a novel generation of drugs for the treatment of bacterial and fungal infections . In addition, the wide spectrum of antimicrobial activities reported for these molecules suggests they potential benefit in the treatment of cancer  and viral  or parasitic infections . Different therapeutic applications of these compounds, from topical administration to systemic treatment of infections, have been developed by several biotechnological companies  Interestingly, to date, clinical Phase I and II trials have shown a limited resistance for the bacterial strains tested (Zasloff, 2002). These features make the antibiotic peptides a powerful arsenal of molecules that could be the antimicrobial drugs of the new century as an innovative response to the increasing problem of MDR .

Resistance to chemical antibiotics: an unsolved and growing problem

The importance of the innate immune response in living organisms

Differentiating  antimicrobial peptides

Proposed mechanism of action of cationic peptides

The importance of  AMPs in humans

Discussion

Is there an induced resistance to AMPs?

AMPs and  biotechnology: Is there a promising future?

Relevancy of AMPs: Is there more to come?

References

HANCOCK, R.E.W. and CHAPPLE, D.S. Peptide antibiotics (Minireview). Antimicrobial Agents Chemotherapy, 1999, vol. 43, no. 6, p. 1317-1323.

ZASLOFF, M. Antimicrobial peptides of multicellular organisms. Nature, 2002, vol. 415, no. 6870, p. 389-395.