Department of Dental Materials and Prosthodontics, School of Dentistry, São Paulo State University (UNESP), Rua Humaitá, 1680, 14801-903, Araraquara, SP, Brazil.
Department of Restorative Dental Sciences, College of Dentistry, University of Florida, Center Dr. 1395, Gainesville, 32610, FL, USA.
Photodiagnosis Photodyn Ther. 2020 Jun;30:101760. doi: 10.1016/j.pdpdt.2020.101760. Epub 2020 Apr 10.
Staphylococcus aureus have a great ability to become rapidly resistant to conventional antimicrobial therapies. This study evaluated the efficacy of antimicrobial photodynamic therapy (aPDT) mediated by Curcumin (Cur) and light-emitting diode (LED) in the inactivation of biofilms of methicillin susceptible and resistant S. aureus (MSSA and MRSA, respectively).
Biofilms were treated with Cur (20, 40 or 80 μM) and illuminated with LED source (455 ± 3 nm; 5.28 J/cm) (aPDT groups), or treated either with Cur or LED only. Other samples were not exposed to Cur or LED (negative control). The biofilms viability after all experimental conditions were evaluated by counting the number of colonies (CFU/mL) and XTT assay. Additional samples were also evaluated by LIVE/DEAD® staining using confocal laser scanning microscopy (CLSM). Data were analyzed by ANOVAs followed by the Games-Howell post hoc test (α = 0.05).
For both strains, all aPDT groups significantly reduced both CFU/mL and metabolic activity of biofilms compared to the negative control (p < 0.001). The results were enhanced when 80 μM of Cur was used. CLSM images showed that both bacteria biofilms submitted to aPDT had a large number of red-stained colonies, especially at aPDT80. In general, MRSA biofilms tended to be less susceptible to aPDT than MSSA biofilms.
It can be concluded that aPDT mediated by Cur and LED was an efficient method to inactivate 48 -h biofilms of both S. aureus strains.
金黄色葡萄球菌具有迅速对抗传统抗菌疗法产生耐药性的巨大能力。本研究评估了姜黄素（Cur）和发光二极管（LED）介导的光动力抗菌疗法（aPDT）对耐甲氧西林敏感金黄色葡萄球菌（MSSA）和耐甲氧西林金黄色葡萄球菌（MRSA）生物膜的杀菌效果。
用 Cur（20、40 或 80 μM）处理生物膜，并使用 LED 光源（455 ± 3nm；5.28 J/cm）进行照射（aPDT 组），或仅用 Cur 或 LED 处理。其他样品未暴露于 Cur 或 LED（阴性对照）。通过计数菌落数（CFU/mL）和 XTT 测定评估所有实验条件后生物膜的活力。还通过使用共聚焦激光扫描显微镜（CLSM）的 LIVE/DEAD®染色评估了其他样品。通过方差分析（ANOVA）和 Games-Howell 事后检验（α=0.05）对数据进行分析。
对于两种菌株，所有 aPDT 组与阴性对照组相比，均显著降低 CFU/mL 和生物膜代谢活性（p<0.001）。使用 80 μM 的 Cur 时，结果得到增强。CLSM 图像显示，两种细菌生物膜均经 aPDT 处理后，有大量红色染色的菌落，尤其是在 aPDT80 时。一般来说，MRSA 生物膜比 MSSA 生物膜对 aPDT 的敏感性低。
可以得出结论，由 Cur 和 LED 介导的 aPDT 是一种有效灭活两种金黄色葡萄球菌菌株 48 小时生物膜的方法。
