Posted by: Glow-worm PJ22 MAY 2013
The development of a potential new treatment for drug-resistant bacteria will be reported in the June issue of the Journal of Antimicrobial Agents and Chemotherapy.
Cationic antimicrobial peptides (CAPs) are small peptides that are ubiquitous in nature, having evolved as part of the defence mechanism of higher organisms. They have an amino acid composition that gives them a positive electrical charge.
The exact mode of action of CAPs remains elusive, but most are thought to act on bacterial cell membranes, which are rich in negatively charged phospholipids. The CAPs disrupt these membranes, either by the formation of pores or by barrier disruption. CAPs can be synthetically engineered, when they are known as eCAPs.
Much recent research has been conducted to ascertain which lengths and sequences of amino acid are best for optimal antimicrobial activity.
Scientists at the University of Pittsburgh, conducting basic research on HIV proteins, discovered that a particular sequence of amino acids on the tail end of the HIV allows the virus to infect host cells. The team was able to reproduce this sequence in the form of an eCAP, and laboratory tests demonstrated that it rapidly destroys bacteria resistant to most antibiotics. Because they are specifically attracted to target bacteria, the eCAPs can cause disruption and bacterial cell death in minutes or even seconds.
Further research has shown that they are also effective against
so-called biofilms, communities of bacteria resistant to antibiotics that form a protective outer film for the bacterial population in the centre, such as those found in the lungs of cystic fibrosis sufferers. The eCAPs appear to be able to penetrate rapidly this outer biofilm to destroy the bacteria within.
The future development of eCAPs is cause for optimism in the treatment of life-threatening antibiotic-resistant infections.