Center of Biophotonics, Federal University of Bahia, 62, Araujo Pinho Ave, Canela, Salvador, BA 40110-150, Brazil; National Institute of Basic Optics and Applied to Life Science, 400, Trabalhador São-Carlense Ave, Parque Arnold Schimidt, São Carlos, SP CEP:13566-590, Brazil.
Center of Biophotonics, Federal University of Bahia, 62, Araujo Pinho Ave, Canela, Salvador, BA 40110-150, Brazil.
J Photochem Photobiol B. 2019 Nov;200:111654. doi: 10.1016/j.jphotobiol.2019.111654. Epub 2019 Oct 23.
The Enterococcus faecalis is a microorganism that causes multiple forms of resistance to a wide range of drugs used clinically. aPDT is a technique in which a visible light activates photosensitizer (PS), resulting in generation of reactive oxygen species that kill bacteria unselectively via an oxidative burst. aPDT is an alternative to antibiotics with the advantage of not causing resistance. The search for an alternative treatment of infections caused by E. faecalis, without using antibiotics, is off great clinical importance. The aim of present investigation was to assess the efficacy of using 3.32 ηg/mL of 1,9-dimethylmethylene blue (DMMB) as photosensitizer associated with the use of either Laser (λ660 nm) or LED (λ632 ± 2 nm) using different energy densities (6, 12 and 18 J/cm) to kill E. faecalis in vitro. Under different experimental conditions, 14 study groups, in triplicate, were used to compare the efficacy of the aPDT carried out with either the laser or LED lights using different energy densities associated to DMMB. The most probable number method (MPN) was used for quantitative analysis. Photodynamic antimicrobial effectiveness was directly proportional to the energy density used, reaching at 18 J/cm, 99.999998% reduction of the counts of E. faecalis using both light sources. The results of this study showed that the use of 3.32 ηg/mL of DMMB associated with the use 18 J/cm of LED light (λ632 ± 2 nm) reduced >7-log counts of planktonic culture of E. faecalis.
粪肠球菌是一种微生物，它会导致多种形式的耐药性，对临床广泛使用的多种药物产生耐药性。 aPDT 是一种技术，其中可见光激活光敏剂（PS），导致活性氧的产生，通过氧化爆发非选择性地杀死细菌。 aPDT 是抗生素的替代品，其优点是不会引起耐药性。寻找替代治疗粪肠球菌引起的感染的方法，而不使用抗生素，具有重要的临床意义。本研究的目的是评估使用 3.32 ηg/mL 的 1,9-二亚甲基甲蓝（DMMB）作为光敏剂联合使用激光（λ660nm）或 LED（λ632±2nm），使用不同的能量密度（6、12 和 18 J/cm）来杀死体外粪肠球菌的疗效。在不同的实验条件下，使用 14 个研究组，每组一式三份，比较使用不同能量密度的激光或 LED 灯联合 DMMB 进行 aPDT 的疗效。最可能数法（MPN）用于定量分析。光动力抗菌效果与使用的能量密度直接成正比，使用两种光源，当能量密度达到 18 J/cm 时，粪肠球菌的计数减少了 99.999998%。本研究结果表明，使用 3.32 ηg/mL 的 DMMB 联合使用 18 J/cm 的 LED 光（λ632±2nm）可减少浮游培养物中粪肠球菌的计数>7 对数。
