In light of the struggle against anti-biotic resistant bacteria, a new line of research is attempting to develop a different type of antimicrobial therap, called antimicrobial peptides (AMP). This research is based on small molecules of the innate immune system that exhibit microbicidal and immuno-modulatory activity.
Antimicrobial peptides are small, widely varying in their sequence and structure, and positively charged proteins, which are produced as part of the innate immune system of organisms. AMPs can also indirectly facilitate microbial defense by recruiting phagocytes to the site of infection and boosting the immune cells’ killing activity. The modes of action by which antimicrobial peptides kill bacteria is varied and includes disrupting membranes, interfering with metabolism, and targeting cytoplasmic components.
AMPs’ wide distribution and the apparent lack of resistance in bacterial populations make them attractive potential therapeutics and complements to conventional antibiotic therapy because in contrast to conventional antibiotics they do not appear to induce antibiotic resistance while they generally have a broad range of activity, are bacteriocidal as opposed to bacteriostatic and require a short contact time to induce killing.
However, as with antibiotics, bacteria can evolve resistance to AMPs. However, in a research paper published in Biology Letters, scientists have demonstrated that by developing bacteria to evolve resistance to one AMP can confer some cross-resistance to a natural host-defense peptide. This means that evolution of resistance to a synthetic AMP, designed purely for therapeutic usage, could possibly lead to cross-resistance with human AMPs.
Hopefully this is a major step forward in drug research.
The paper reference is:
M.G.J.L. Habets and M.A. Brockhurst, “Therapeutic antimicrobial peptides may compromise natural immunity,” Biology Letters, doi:10.1098/rsbl.2011.1203.