Photodynamic Antimicrobial Chemotherapy (PACT) Using Phenothiazines Derivatives Associated with the Red Laser against Staphylococcus aureus

Susana C. P. S. Oliveira; Gustavo M. P. Santos; Juliana S. C. Monteiro; Anderson F. S. Miranda; Fernando J. P. Sampaio; Maria F. M. Gesteira; Fátima A. A. Zanin; Marcos A. V. Santos; Antônio L. B. Pinheiro

doi:10.1117/12.2005560

5 March 2013 Photodynamic antimicrobial chemotherapy (PACT) using phenothiazines derivatives associated with the red laser against staphylococcus aureus

Susana C. P. S. Oliveira, Gustavo M. P. Santos, Juliana S. C. Monteiro, Anderson F. S. Miranda, Fernando J. P. Sampaio, Maria F. M. Gesteira, Fátima A. A. Zanin, Marcos A. V. Santos, Antônio L. B. Pinheiro

Author Affiliations +

Proceedings Volume 8569, Mechanisms for Low-Light Therapy VIII; 85690P (2013) https://doi.org/10.1117/12.2005560
Event: SPIE BiOS, 2013, San Francisco, California, United States

Abstract

The objective of this study was to evaluate the bactericidal effect of photodynamic antimicrobial chemotherapy (PACT) using phenothiazinium dye (Toluidine blue O and methylene blue) at a low concentration of 1μg/mL irradiated with the red laser at doses of 2.4 e 4.8 J/cm² on strain of Staphylococcus aureus (ATCC 23529) in vitro. For this research, tests were performed in triplicate and the samples were distributed into six test groups: (L_-P_-) Negative control (L1₊P_-) and (L2₊P_-) bacterial suspensions were irradiated with laser energy 2.4 and 4.8 J/cm² respectively in the absence of photosensitizer; (L1₊P₊) and (L2₊P₊) bacterial suspensions were irradiated with laser in the presence of 1μg/ml of photosensitizer and finally (L_-P₊) bacterial suspensions only in the presence of phenothiazinium dye. Therefore, were analyzed the potential bactericidal PACT by counting of colony-forming units and analyzed statistically (ANOVA, Tukey test, p<0.05). The results showed that the negative control group when compared with laser group (L2₊P_-) it was observed a statistically significant increase (p<0.01) which L2₊P_- showed a higher number of CFU, on the other hand when compared to L1₊P_- no statistically significant difference was found, relation to the groups submitted to PACT, only showed a statistically significant reduction relative to the group irradiated L2₊P₊ (p<0.01) that showed a decrease in the number of CFU. There was no statistically significant difference between the groups submitted to PDT (L1₊P₊ and L2₊P₊). Although the results of this study have shown a reduction in average number of colony forming units by the appropriate laser-dye treatment combination, it needs further investigation.

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Susana C. P. S. Oliveira, Gustavo M. P. Santos, Juliana S. C. Monteiro, Anderson F. S. Miranda, Fernando J. P. Sampaio, Maria F. M. Gesteira, Fátima A. A. Zanin, Marcos A. V. Santos, and Antônio L. B. Pinheiro "Photodynamic antimicrobial chemotherapy (PACT) using phenothiazines derivatives associated with the red laser against staphylococcus aureus", Proc. SPIE 8569, Mechanisms for Low-Light Therapy VIII, 85690P (5 March 2013); https://doi.org/10.1117/12.2005560

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