Use of photodynamic therapy associated with ozone in the initiation of Pythium insidiosum.

• Grant number: 20/14324-6
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: March 01, 2021
• End date: December 31, 2021
• Field of knowledge: Agronomical Sciences - Veterinary Medicine - Animal Pathology
• Principal Investigator: Jair Camargo Ferreira
• Grantee: Viviani Silva Rodrigues
• Host Institution: Pró-Reitoria Adjunta de Pesquisa e Pós-Graduação. Universidade de Franca (UNIFRAN). Franca , SP, Brazil

Abstract

The goal of the present study will be to characterize the antimicrobial action of the photodynamic therapy (PDT) associated with ozone (O3) gas against Pythium insidiosum isolated from horses. Samples of the pathogen will be divided into four groups (n = 5 samples/group) according to the treatment: Gas-O3, TFD, TFD-O3 and Control groups. Gas-O3 group will be exposed to the O2-O3 gas mixture (72¼g O3 mL-1 and flow of 125mL gas min-1) for 30 minutes. In the TDF group, P. insidiosum will be immersed for three seconds in a blue methylene solution (100 mg mL-1) and incubated in the dark for 30 minutes at 35ÚC. The samples will be posteriorly irradiated for 10 minutes with an iodine laser with light absorption at a wavelength of 660nm, irradiance of 65 mW cm2 and fluency of 70 J cm2. Samples from the TDF-O3 group were irradiated for 10 minutes, in the absence of photosensitizer, with an iodine laser (wavelength of 660nm, irradiance of 65 mW cm2 and fluency of 70 J cm2). Finally, the samples will be exposed to O3 gas as described for gas-O3 group. Treatment and Control groups will be cultured for 14 days at 35ºC. Samples that do not show growth at the end of the first 14 daysr will be recultured for an additional seven days. The end-points to be evaluatted are: a) Growth inhibition rate, b) post-treatment superficial architecture of the pathogen and d) germicidal/germistatic action of each treatments.