Bacterial reduction and resistance after multiple cycles of photodynamic therapy

• Grant number: 16/10310-5
• Support type: Scholarships in Brazil - Doctorate (Direct)
• Effective date (Start): September 01, 2016
• Effective date (End): July 31, 2018
• Field of knowledge: Health Sciences - Dentistry - Dental Clinics
• Principal researcher: Carla Raquel Fontana Mendonça
• Grantee: Lucas Henrique de Paula Zago
• Home Institution: Faculdade de Ciências Farmacêuticas (FCFAR). Universidade Estadual Paulista (UNESP). Campus de Araraquara. Araraquara , SP, Brazil

Abstract

In this study, clinical samples and ATCC strains will be compared by evaluating the reduction and the resistance of periodontal bacteria after successive cycles of Photodynamic Therapy (PDT) curcumin, chlorin e6 and methylene blue mediated. These conditions will be tested both suspension and multiple species biofilm. Initially ATCC strains (Enterococcus faecalis (ATCC 29212), Fusobacterium nucleatum subsp. nucleatum (ATCC 25586) and Propionibacterium acnes (ATCC 6919) will be tested in order to mimic the clinical condition. In a second step, clinical samples (sub gingival biofilm) from patients in the treatment of periodontal disease will be evaluated. All samples will be grown anaerobically for the formation of the biofilm in vitro. Molecular identification and quantification of clinical samples will also be carried out. Photosensitizers and light according to the absorption spectrum will be employed. The optimal number of cycles for reduction of bacterial suspension and biofilm will be determined, as well as the possibility aimed to assess the potential of microorganisms to develop such resistance after repeated applications of photodynamic therapy. Cell viability will be determined by counting colony forming units (CFU/mL), XTT, Minimum Inhibitory Concentration (MIC), image analysis via scanning electron microscopy and quantification of the total biomass. Potential studies of microorganisms to develop resistance to PDT are extremely important because so far the results are still scarce and controversial. (AU)

Scientific publications

(References retrieved automatically from Web of Science and SciELO through information on FAPESP grants and their corresponding numbers as mentioned in the publications by the authors)

DE PAULA ZAGO, LUCAS HENRIQUE; DE ANNUNZIO, SARAH RAQUEL; DE OLIVEIRA, KLEBER THIAGO; BARBUGLI, PAULA ABOUD; VALDES, BELEN RETAMAL; FERES, MAGDA; FONTANA, CARLA RAQUEL. Antimicrobial photodynamic therapy against metronidazole-resistant dental plaque bacteria. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY, v. 209, AUG 2020. Web of Science Citations: 0.