Phagomimetic action of antimicrobial agents

Area of Science:

• Biochemistry
• Microbiology
• Pharmacology

Background:

• Many drug molecules, including antibiotics, possess electron transfer capabilities.
• These molecules can generate reactive oxygen species (ROS) by transferring electrons to oxygen, producing superoxide and hydrogen peroxide.
• In the presence of redox-active iron, Fenton chemistry generates highly damaging hydroxyl radicals.

Purpose of the Study:

• To propose a common mechanism for microbial killing utilized by both phagocytic cells and antibiotics.
• To explore the role of reactive oxygen species (ROS) in antibiotic-mediated microbial inhibition.
• To investigate the similarity between the evolved microbial killing mechanisms in phagocytic cells and the chemical actions of certain drugs.

Main Methods:

• Review of existing literature on drug molecule redox capabilities and ROS generation.
• Analysis of antibiotic mechanisms of action against bacteria, yeasts, and cancer cells.
• Comparison of ROS-generating chemistry in vitro with biological processes in phagocytic cells.

Main Results:

• Numerous antibiotics readily generate ROS, contributing to their antimicrobial and anticancer effects.
• The ROS-generating chemistry of antibiotics closely resembles the oxidative stress mechanisms employed by phagocytic immune cells.
• Antibiotics demonstrate significant in vivo efficacy at concentrations below their in vitro minimum inhibitory concentrations, suggesting non-traditional mechanisms.

Conclusions:

• A shared mechanism involving ROS exploitation for microbial killing exists between phagocytic cells and certain antibiotics.
• Antibiotics may leverage oxidative stress pathways, similar to innate immunity, to achieve therapeutic effects.
• Understanding this common mechanism could lead to novel therapeutic strategies targeting microbial infections and cancer.