Why do natural antimicrobial peptides remain successful while antibiotics fail?
It is impossible to accurately describe the level of bacterial resistance to insect antimicrobial peptides as comparatively so little research has been conducted on this area. However, what is clear is that antimicrobial peptides can still successfully clear infections despite bacteria being exposed to their action for millions of years. One possibility is that if the host has evolved counter strategies to the development of pathogen resistance then we would not see the evidence of this resistance. This obviously contrasts with medical antibiotics which are synthetic and therefore evolutionarily static. However, studies looking at this possibility have found that no evidence for co-evolution occurring with antimicrobial peptides and the pathogen. Therefore, there must be some characteristic of the antimicrobial peptides or the way in which they are administered which limits the development of bacterial resistance. Four possible characteristics are shown in the following diagram.
