Antimicrobial photodynamic therapy proved not to induce bacterial resistance (Conference Presentation)

Author(s):  
Laura M. de Freitas ◽  
Ana L. Blanco ◽  
Carla R. Fontana
2017 ◽  
Vol 376 ◽  
pp. 54-65 ◽  
Author(s):  
Monica Laura Dascalu (Rusu) ◽  
Codruta Sarosi ◽  
Marioara Moldovan ◽  
Mândra Eugenia Badea

Photodynamic therapy (PDT) also known as Phototherapy or Photo chemotherapy involves the use of a photoactive dye (photosensitive) which is activated by exposure to light of a certain wavelength in the presence of oxygen. Dentists have to deal regularly with oral infections which untreated may cause systemic infections. Oral infections such as caries, periodontal infections and infections of the oral mucosa are available lighting so photodynamic therapy is particularly suitable for oral diseases [1,2]. Antimicrobial chemical treatment is nowadays widely used in the prophylaxis and treatment of inflammation-induced plaque with the risk of resistance development. The use of photodynamic therapy as a therapeutic approach can eliminate this risk, however. Studies in the literature show that both Gram-positive bacteria and Gram-negative bacteria are susceptible to the treatment. Among the advantages of using this method is counted rapid elimination of bacteria, minimal chances of developing bacterial resistance and safety in terms of host tissue and existing normal microflora in the oral cavity [3]. Antimicrobial photodynamic therapy (aPDT) by photochemical reaction uses light at a specific wavelength to activate a nontoxic photosensitizer (PS) in the presence of oxygen to produce cytotoxic products. There are different PSs used in dentistry including methylene blue (MB), toluidine blue O (TBO), indocyanine green (ICG) and curcumin [4].


Author(s):  
Pier Poli ◽  
Francisley Avila Souza ◽  
Mattia Manfredini ◽  
Carlo Maiorana ◽  
Mario Beretta

Not required for Clinical case letters according to the authors' guidelines.


Antibiotics ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 869
Author(s):  
Beatriz Müller Nunes Souza ◽  
Juliana Guerra Pinto ◽  
André Henrique Correia Pereira ◽  
Alejandro Guillermo Miñán ◽  
Juliana Ferreira-Strixino

Staphylococccus aureus is a ubiquitous and opportunistic bacteria associated with high mortality rates. Antimicrobial photodynamic therapy (aPDT) is based on the application of a light source and a photosensitizer that can interact with molecular oxygen, forming Reactive Oxygen Species (ROS) that result in bacterial inactivation. This study aimed to analyze, in vitro, the action of aPDT with Photodithazine® (PDZ) in methicillin-sensitive Staphylococcus aureus (MSSA) and methicillin-resistant Staphylococcus aureus (MRSA) strains. The strains were incubated with PDZ at 25, 50, 75, and 100 mg/L for 15 min and irradiated with fluences of 25, 50, and 100 J/cm2. The internalization of PDZ was evaluated by confocal microscopy, the bacterial growth by counting the number of colony-forming units, as well as the bacterial metabolic activity post-aPDT and the production of ROS. In both strains, the photosensitizer was internalized; the production of ROS increased when the aPDT was applied; there was a bacterial reduction compared to the control at all the evaluated fluences and concentrations; and, in most parameters, it was obtained complete inactivation with significant difference (p < 0.05). The implementation of aPDT with PDZ in clinical strains of S. aureus has resulted in its complete inactivation, including the MRSA strains.


2021 ◽  
Vol 14 (7) ◽  
pp. 603
Author(s):  
Vanesa Pérez-Laguna ◽  
Isabel García-Luque ◽  
Sofía Ballesta ◽  
Antonio Rezusta ◽  
Yolanda Gilaberte

The present review covers combination approaches of antimicrobial photodynamic therapy (aPDT) plus antibiotics or antifungals to attack bacteria and fungi in vitro (both planktonic and biofilm forms) focused on those microorganisms that cause infections in skin and soft tissues. The combination can prevent failure in the fight against these microorganisms: antimicrobial drugs can increase the susceptibility of microorganisms to aPDT and prevent the possibility of regrowth of those that were not inactivated during the irradiation; meanwhile, aPDT is effective regardless of the resistance pattern of the strain and their use does not contribute to the selection of antimicrobial resistance. Additive or synergistic antimicrobial effects in vitro are evaluated and the best combinations are presented. The use of combined treatment of aPDT with antimicrobials could help overcome the difficulty of fighting high level of resistance microorganisms and, as it is a multi-target approach, it could make the selection of resistant microorganisms more difficult.


Author(s):  
Dariane Clerici Jornada ◽  
Rafael de Queiroz Garcia ◽  
Carolina Hahn da Silveira ◽  
Lino Misoguti ◽  
Cleber Renato Mendonça ◽  
...  

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