Pereira de Lima Carvalho Denise, Guerra Pinto Juliana, Di Paula Costa Sorge Camila, Rodrigues Benedito Fabiana Regis, Khouri Sonia, Ferreira Strixino Juliana
Laboratory of Photodynamic Therapy, LEVB-Institute of Research & Development-Univap, University of Vale do Paraíba/Faculty of Health Sciences/IP&D, Av. Shishima Hifumi, 2911, Urbanova São José dos Campos, 12244, São Paulo, Brazil.
Lasers Med Sci. 2014 Jan;29(1):113-20. doi: 10.1007/s10103-013-1283-8. Epub 2013 Mar 1.
The effective treatment of infected wounds continues to be a serious challenge, mainly due to the rise of antibiotic-resistant bacteria. Photodynamic therapy (PDT) refers to the topical or systemic administration of a non-toxic, photosensitizing agent (PS), followed by irradiation with visible light of a suitable wavelength. The possibility of applying the PDT locally is what makes it so favorable to the treatment of infected wounds. The goal of this study was to evaluate the action of the PDT in the inactivation in vitro of microorganisms coming from infected wounds, using methylene blue (MB) and photodithazine (PDZ) as the PS and comparing the efficacy of these two compounds for PDT on bacteria. For the application of PDT, isolated microorganisms identified from material collected from wounds were suspended in a saline solution containing 10(6) viable cells/ml. Each isolated microorganism was submitted to PDT with MB and with PDZ in accordance with the following treatment groups: N/T--no treatment; T1--PDT with PDZ; T2--PDT with MB; T3--irradiation without PS; T4--treatment with PDZ without light; and T5--treatment with MB without light. As a light source, an LED-based device was used (Biopdi/Irrad-Lead 660), composed of 54 LEDs, each with 70 mW of power in the 660 nm region of the electromagnetic spectrum. Each tray of 96 wells was irradiated with an intensity of 25 mW/cm(2) and a dose of light of 50 J/cm(3) for 33 min. All the tests were made in duplicate. It was then concluded that the PDT with PDZ was capable of inhibiting the growth of gram-positive bacteria samples, however it did not have the same effect on gram-negative bacteria, which showed growth greater than 100,000 CFU; the PDT with MB showed an effectiveness on gram-positive as well as gram-negative bacteria, for it was able to inhibit bacterial growth in both cases.
感染伤口的有效治疗仍然是一项严峻挑战，主要原因是抗生素耐药菌的增多。光动力疗法（PDT）是指局部或全身给予无毒的光敏剂（PS），随后用合适波长的可见光进行照射。PDT局部应用的可能性使其在感染伤口治疗中极具优势。本研究的目的是评估PDT对来自感染伤口的微生物的体外灭活作用，使用亚甲蓝（MB）和光二嗪（PDZ）作为PS，并比较这两种化合物对细菌的PDT疗效。为了应用PDT，从伤口采集的材料中鉴定出的分离微生物悬浮于含有10⁶个活细胞/毫升的盐溶液中。每种分离微生物按照以下治疗组分别接受用MB和PDZ的PDT：N/T——未治疗；T1——用PDZ的PDT；T2——用MB的PDT；T3——无PS照射；T4——用PDZ但无光处理；T5——用MB但无光处理。作为光源，使用了一种基于发光二极管的设备（Biopdi/Irrad - Lead 660），由54个发光二极管组成，每个在电磁光谱的660纳米区域功率为70毫瓦。每个96孔板以25毫瓦/平方厘米的强度和50焦/立方厘米的光剂量照射33分钟。所有测试均重复进行。结果得出，用PDZ的PDT能够抑制革兰氏阳性菌样本的生长，然而对革兰氏阴性菌没有同样效果，革兰氏阴性菌显示生长超过100,000 CFU；用MB的PDT对革兰氏阳性菌和革兰氏阴性菌均显示出有效性，因为在两种情况下它都能够抑制细菌生长。
