Evaluation of the impact of catalase inhibitor use in conjunction with antimicrobial photodynamic therapy in S. aureus biofilm

• Grant number: 22/08749-0
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Effective date (Start): September 01, 2022
• Effective date (End): February 28, 2023
• Field of knowledge: Biological Sciences - Microbiology - Applied Microbiology
• Principal Investigator: Carla Raquel Fontana Mendonça
• Grantee: Renata Laurintino de Santana
• Host Institution: Faculdade de Ciências Farmacêuticas (FCFAR). Universidade Estadual Paulista (UNESP). Campus de Araraquara. Araraquara , SP, Brazil

Abstract

Antimicrobial photodynamic therapy (PDTa) is an efficient alternative in the treatment of bacterial infections for presenting several advantages, such as being a non-invasive method, easy laboratory application, and painless protocols. This type of therapy has gained prominence in various health sectors such as dermatology, oncology, gynecology, and urology, and recently it has been studied as a strategy to combat antimicrobial resistant bacteria. Its mechanism of action is based on the interaction between a light-sensitive substance called photosensitizer (FS) with light. The FS, when irradiated at the appropriate light length and in the presence of oxygen, is elevated to the excited state and can interact with molecular oxygen indirectly via charge transfer by reaction with biomolecules and generation of radicals forming reactive oxygen species (ROS) (type I reaction) or directly (type II reaction), with the formation of singlet oxygen. The ROS comes into contact with the cells of the microorganisms, resulting in DNA damage and damage to the cytoplasmic membrane, which inactivates the enzyme transfer system. One way used by cells to try to circumvent the action of ROS is through antioxidant enzymes, such as Superoxide Dismutase (SOD), which catalyzes superoxide into peroxide, Catalase (CAT), which acts in the breakdown of H2O2 into O2 and H2O, and Glutathione Peroxidase (GSH-Px), which acts on peroxides and uses the reducing potential of the reduced glutathione tripeptide, which can decrease the effectiveness of TFDa. In this study, the effects provided by methylene blue (AM) mediated TFDa treatment with the use of catalase inhibitor, 3-amino-1,2,4-triazole (3-AT) inhibitor on Staphylococcus aureus biofilm will be evaluated.(AU)