Mammals’ antimicrobial peptides: potential and limitations for the treatment of Staphylococcus aureus infections

Abstract

Antimicrobial peptides (AMPs) are small molecules produced by virtually all living organisms as a part of the innate immune system. They present a broad spectrum antimicrobial activity against a myriad of microorganisms, but also anti-inflammatory, immunomodulatory and antitumor effects, among others. Therefore, it was our objective to compile and analyze the current information about natural and synthetic AMPs, regarding their general mechanisms of action, potentials, and limitations for clinical use, especially for the treatment of Staphylococcus aureus infections. Furthermore, we intended to briefly discuss new routes of administration and the emergence of bacterial resistance to AMPs. To do so, two databases, PubMed and Scopus, and the keywords “Staphylococcus aureus”, “antimicrobial peptide” and “novel antibiotics” were used, and the articles were filtered by the English language for the period between 2011 and 2016. We found that AMPs possess different properties, with characteristic antimicrobial activities and secondary effects. Moreover, we also pointed some modifications that could be used to design new AMPs and different routes of administration that could be used to improve AMP capacity or to adapt it to a specific purpose, such as preventing biofilm formation in catheters or treating a specific disease. On the other hand, they also present limitations that include: development of bacterial resistance, cytotoxicity, and reduced stability, sometimes lower efficacy when compared to the actual treatment, high costs of production and also some inconsistent results between articles, which we believe that may be related to differences in methods and/or strains of S. aureus investigated.