Antimicrobial use of reactive oxygen therapy: current insights

Abstract

Infections caused by drug-resistant pathogens are a global public health problem. The introduction of a new antimicrobial strategy is an unavoidable option for the management of drug-resistant pathogens. Induction of high levels of reactive oxygen species (ROS) by several procedures has been extensively studied for the treatment of infections. In this article, the general aspects of ROS production and the common procedures that exert their antimicrobial effects due to ROS formation are reviewed. ROS generation is the antimicrobial mechanism of nanoparticles, hyperbaric oxygen therapy, medical honey, and photodynamic therapy. In addition, it is an alternative bactericidal mechanism of clinically traditional antibiotics. The development of ROS delivery methods with a desirable selectivity for pathogens without side effects for the host tissue may be a promising approach for the treatment of infections, especially those caused by drug-resistant organisms.

Keywords: antibiotic resistance; infections; reactive oxygen species.

Figure 1

ROS formation and scavenging. Notes: Consecutive addition of ē and O₂ is associated with the ROS formation. O₂•− is inactivated enzymatically by SOD. catalase scavenge H₂O₂. Abbreviations: Ahp, alkyl hydroperoxide reductase; ROS, reactive oxygen species; SOD, superoxide dismutase.

Figure 2

ROS induction by antibiotics. Notes: Bactericidal antimicrobial agents by interacting with cellular specific targets induce the lethal cellular effect. In addition to special mechanisms, they induce the stress pathway that triggers redox-related condition. These conditions are associated with production of toxic reactive species, such as ROS, which induce cellular toxicity and lethal effects. Abbreviation: ROS, reactive oxygen species.

Figure 3

Antimicrobial activity of PDT. Notes: Cationic PS can bind to both Gram-negative and Gram-positive bacteria. Anionic PS generally binds only to Gram-positive bacteria. In the presence of light, PS exits (activated) and induces ROS formation that has antimicrobial effects. Abbreviations: PDT, photodynamic therapy; PS, photosensitizer; ROS, reactive oxygen species.

Figure 4

The procedure that inhibits microbial growth by ROS formation and biologic targets. Notes: In addition to being an alternative bactericidal mechanism of clinically traditional antibiotics, ROS generation is the antimicrobial mechanism of HBOT, medical honey, and photodynamic therapy. The cellular targets for the toxic effects of ROS are DNA and proteins and lipids. Abbreviations: HBOT, hyperbaric oxygen therapy; ROS, reactive oxygen species.