Otimização da Terapia Fotodinâmica Antimicrobiana em S. aureus via inibição da catalase
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Data
2022-09-26
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Universidade Estadual Paulista (Unesp)
Resumo
Uma alternativa ao combate ao uso irracional de antimicrobianos é a terapia fotodinâmica antimicrobiana (TFDa), uma forma moderna e não invasiva de terapia, a qual tem seu mecanismo de ação fundamentado na ativação pela irradiação de um fotossensibilizador (FS) na presença de oxigênio e sob fluências especificas de luz no comprimento de onda adequado. O objetivo desse estudo é avaliar possíveis alterações da ação antimicrobiana da TFDa mediadas por Azul de metileno (AM) e Curcumina (CUR) na presença do inibidor de catalase 3-AT sobre S. aureus ATCC 25923 em fase planctônica. Para tanto foram realizados os testes de Concentração Inibitória Mínima (MIC) e Concentração Bactericida Mínima (CBM) sobre o 3-AT através do método de microdiluição, a avaliação da fotodegradação dos FS, a padronização dos parâmetros ideais de TFDa e a avaliação de sinergismo entre TFDa e 3-AT em diferentes tempos de inibição (10 a 40 minutos). A análise estatística dos dados foi feita através do teste de Análise de Variância (one-way ou two-way ANOVA) com pós-teste de Tukey. O 3-AT não apresentou MIC e CBM para as concentrações avaliadas e demonstrou um padrão de redução do crescimento bacteriano na presença do inibidor, sem morte bacteriana após a retirada do mesmo. Os parâmetros ideais para TFDa mediada por AM solubilizada em salina estéril e por CUR dissolvida em DMSO 1% e sacarose 0,5% foram 10 minutos de pré-irradiação, 50 µg/mL AM, 72,96 mW/cm2 , 65,66 J/cm2 e 30 minutos de pré-irradiação, 6,25 µg/mL CUR, 55 mW/cm2 e 25 J/cm2 , respectivamente. Na terapia combinada (TC) entre TFDa e 3-AT foram avaliados diferentes tempos de inibição da catalase necessário para redução bacteriana total. Com isso, pode-se concluir que a TC demonstrou possuir sinergismo entre TDFa e 3-AT, ser dependente do tempo de inibição da catalase e do tempo de pré-irradiação dos FSs e ter grande potencial para estudos futuros.
An alternative to combating the irrational use of antimicrobials is antimicrobial photodynamic therapy (aPDT), a modern and non-invasive form of therapy, which has its mechanism of action based on the activation by irradiation of a photosensitizer (PS) in the presence of oxygen and under specific fluências of light at the appropriate wavelength. The aim of this study is to evaluate possible alterations in the antimicrobial action of aPDT mediated by Methylene Blue (MB) and Curcumin (CUR) in the presence of the catalase inhibitor 3-AT on S. aureus ATCC 25923 in planktonic phase. For that, the tests of Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) were carried out on 3-AT through the microdilution method, the evaluation of the photodegradation of the PS, the standardization of the ideal parameters of PDTa and the evaluation of synergism between PDTa and 3-AT at different inhibition times (10 to 40 minutes). Statistical data analysis was performed using the Analysis of Variance test (one-way or two-way ANOVA) with Tukey's post-test. 3-AT did not show MIC and CBM at the concentrations evaluated and showed a pattern of growth reduction in the presence of the inhibitor, without bacterial death after its withdrawal. The ideal parameters for aPDT mediated by MB solubilized in sterile saline and by CUR dissolved in 1% DMSO and 0.5% sucrose were 10 minutes pre-irradiation, 50 µg/mL MB, 72.96 mW/cm2, 65.66 J/cm2 and 30 minutes pre-irradiation, 6.25 µg/mL CUR, 55 mW/cm2 and 25 J/cm2, respectively. In combined therapy (CT) between aPDT and 3-AT, different catalase inhibition times required for total bacterial reduction were evaluated. Therefore, it can be concluded that CT demonstrated synergism between aPDT and 3-AT, it is dependent on catalase inhibition time and pre-irradiation time of PSs and has great potential for future studies.
An alternative to combating the irrational use of antimicrobials is antimicrobial photodynamic therapy (aPDT), a modern and non-invasive form of therapy, which has its mechanism of action based on the activation by irradiation of a photosensitizer (PS) in the presence of oxygen and under specific fluências of light at the appropriate wavelength. The aim of this study is to evaluate possible alterations in the antimicrobial action of aPDT mediated by Methylene Blue (MB) and Curcumin (CUR) in the presence of the catalase inhibitor 3-AT on S. aureus ATCC 25923 in planktonic phase. For that, the tests of Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) were carried out on 3-AT through the microdilution method, the evaluation of the photodegradation of the PS, the standardization of the ideal parameters of PDTa and the evaluation of synergism between PDTa and 3-AT at different inhibition times (10 to 40 minutes). Statistical data analysis was performed using the Analysis of Variance test (one-way or two-way ANOVA) with Tukey's post-test. 3-AT did not show MIC and CBM at the concentrations evaluated and showed a pattern of growth reduction in the presence of the inhibitor, without bacterial death after its withdrawal. The ideal parameters for aPDT mediated by MB solubilized in sterile saline and by CUR dissolved in 1% DMSO and 0.5% sucrose were 10 minutes pre-irradiation, 50 µg/mL MB, 72.96 mW/cm2, 65.66 J/cm2 and 30 minutes pre-irradiation, 6.25 µg/mL CUR, 55 mW/cm2 and 25 J/cm2, respectively. In combined therapy (CT) between aPDT and 3-AT, different catalase inhibition times required for total bacterial reduction were evaluated. Therefore, it can be concluded that CT demonstrated synergism between aPDT and 3-AT, it is dependent on catalase inhibition time and pre-irradiation time of PSs and has great potential for future studies.
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Palavras-chave
Terapia Fotodinâmica Antibacteriana, Azul de metileno, Curcumina, Catalase, 3-amino-1,2,4-triazol