PHAGOMIMETIC ACTION OF ANTIMICROBIAL AGENTS

A wide variety of extracted and synthesised drug molecules have electr on transfer capabilities which allow them to generate reactive oxygen species (ROS). In particular, many antibiotics that kill or inhibit ba cteria, yeasts and cancer cells readily transfer electrons to oxygen m aking superoxide and hydrogen peroxide in the process. When suitable r edox active forms of iron are available, Fenton chemistry occurs gener ating the highly damaging hydroxyl radical. This type of chemistry is very similar to that which evolved within phagocytic cells as part of their microbial killing armoury. Many antibiotics, when used in model systems, have well defined pharmacological actions against key cellula r functions, but their clinical usefulness is also often demonstrable at concentrations in vivo well below their in vitro minimum inhibitory concentrations. These observations have led us to propose that a comm on mechanism exists whereby phagocytic cells and antibiotics exploit t he use of ROS for microbial killing.