ABSTRACT
Endolysins are bacteriophage-encoded peptidoglycan hydrolases that accumulate in the cytosol of phage-infected bacterial cells, resulting in eventual cell lysis at the end of the lytic cycle. In view of the prevalence of antibiotic-resistant bacteria, these enzymes represent a truly novel and effective class of antimicrobials in the fight against infection. By recognising unique receptors present in the bacterial cell wall, they exhibit highly specific targeting of their host cell while leaving the normal microflora intact. An interesting feature of endolysins is their modular structure which lends itself to being manipulated by exchanging domains to alter the host spectrum or to improve the catalytic activity. Knowledge of the three dimensional structure is central to determining which domains would be favourable for the creation of designer lysins, tailored for biotechnological applications. Numerous in vitro and in vivo trials have yielded highly encouraging insights into the lytic capabilities and benefits provided by endolysins. Clearly, these potent enzymes possess many advantageous properties which make them suitable for exploitation as antimicrobials. Studies have demonstrated their potential to prevent pathogenic colonization of mucosal membranes and to control bacterial infections, as well as their use as tools in the control o f potential biological weapons such as anthrax, in the biocontrol of bacteria in food and feed and to protect plants from phytopathogenic bacteria. These promising results warrant further investigation into the therapeutic potential of endolysins, conceivably leading to their eventual development as antimicrobial tools.
