Hydrogen peroxide mediated killing of bacteria

Abstract

Polymorphonuclear leukocytes (PMN) or neutrophils have multiple systems available for killing ingested bacteria. Nearly each of these incorporates H2O2 indicating the essential nature of this reactive oxygen intermediate for microbicidal activity. Following ingestion of bacteria by PMN, H2O2 is formed by the respiratory burst which consumes O2 and generates H2O2 from O2 .-. H2O2 is deposited intracellularly near bacteria within phagocytic vacuoles where it can react with the MPO-H2O2-halide system to form toxic hyperchlorous acid (HOCl) and/or possibly singlet oxygen (1O2). H2O2 can also react with O2 .- and/or iron (Fe++) from lactoferrin or bacteria to form the highly toxic hydroxyl radical (.OH). These mechanisms appear important since deficiencies of H2O2 production, myeloperoxidase or lactoferrin frequently increases their owner's susceptibility to infection. In particular, examination of PMN from infection prone patients with chronic granulomatous disease (CGD) most clearly demonstrates the importance of H2O2 in killing of bacteria. CGD PMN lack the capacity to effectively generate H2O2 and subsequently have impaired ability to kill catalase positive (H2O2 producing) but not catalase negative (not H2O2 producing) bacteria. PMN also have catalase and glutathione peroxidase systems in their cytoplasms to protect themselves from the toxicity of H2O2. Finally, while H2O2 is critical for host defense, it can also be released extracellularly and thereby play a significant role in PMN mediated tissue injury.

Protective Role ofd-Amino Acid Oxidase against Staphylococcus aureus Infection

“…For neutrophils, a primary source of the H 2 O 2 used to generate HOCl is NADPH oxidase (24). H 2 O 2 may also have an additional significant role in chronic granulomatous disease, which is a hereditary disease caused by abnormal H 2 O 2 production in neutrophils that is primarily due to defective NADPH oxidase (7,9). D-Amino acid oxidase (DAO) is another H 2 O 2 -generating enzyme, which uses flavin adenine dinucleotide (FAD) as a coenzyme.…”

Photolysis of Hydrogen Peroxide, an Effective Disinfection System via Hydroxyl Radical Formation

“…The hydroxyl radical, one of the reactive oxygen species (ROS), has one unpaired electron in its structure, so that it is apt to deprive other substances of an electron; e.g., it easily oxidizes other substances (8). It is known that the hydroxyl radical is generated in the immunological response in the body to kill invading bacteria (6,9). Therefore, it is believed that the disinfection system based on the bactericidal effect of artificially generated hydroxyl radicals can be used for clinical dentistry.…”

The outer membrane localization of the Neisseria gonorrhoeae MsrA/B is involved in survival against reactive oxygen species

“…PMNs possess a variety of mechanisms for destroying bacteria; of particular importance is the respiratory burst of the phagocytes. This process generates a variety of ROS, including superoxide, hydrogen peroxide, hypochlorite, hydroxyl radical, and peroxynitrite (5)(6)(7)(8). To exist as an effective pathogen, N. gonorrhoeae possesses a number of defenses to resist the host's oxidative burst, including both catalase and peroxidase activities (9,10).…”