Sbarra M S, Di Poto A, Arciola C R, Saino E, Sharma M, Bragheri F, Cristiani I, Speziale P, Visai L
Department of Biochemistry, University of Pavia, Pavia - Italy.
Int J Artif Organs. 2008 Sep;31(9):848-57. doi: 10.1177/039139880803100914.
Photodynamic treatment (PDT) has been proposed as a new approach for inactivation of biofilms associated with medical devices that are resistant to chemical additives or biocides. In this study, we evaluated the antimicrobial activity of merocyanine 540 (MC 540), a photosensitizing dye that is used for purging malignant cells from autologous bone marrow grafts, against Staphylococcus epidermidis biofilms. Effect of the combined photodynamic action of MC 540 and 532 nm laser was investigated on the viability and structure of biofilms of two Staphylococcus epidermidis strains, RP62A and 1457. Significant inactivation of cells was observed when biofilms were exposed to MC 540 and laser simultaneously. The effect was found to be light dose-dependent but S. epidermidis 1457 biofilm proved to be slightly more susceptible than S. epidermidis RP62A biofilm. Furthermore, significant killing of both types of cells was attained even when a fixed light dose was delivered to the biofilms. Confocal laser scanning microscope (CLSM) analysis indicated damage to bacterial cell membranes in photodynamically treated biofilms, while disruption of PDT-treated biofilm was confirmed by scanning electron microscopy (SEM).
光动力疗法（PDT）已被提议作为一种新方法，用于灭活与对化学添加剂或杀菌剂具有抗性的医疗器械相关的生物膜。在本研究中，我们评估了用于从自体骨髓移植物中清除恶性细胞的光敏染料部花青540（MC 540）对表皮葡萄球菌生物膜的抗菌活性。研究了MC 540与532 nm激光联合光动力作用对两种表皮葡萄球菌菌株RP62A和1457生物膜的活力和结构的影响。当生物膜同时暴露于MC 540和激光时，观察到细胞的显著失活。发现该效应与光剂量有关，但表皮葡萄球菌1457生物膜比表皮葡萄球菌RP62A生物膜稍更敏感。此外，即使向生物膜输送固定的光剂量，也能实现对两种类型细胞的显著杀伤。共聚焦激光扫描显微镜（CLSM）分析表明，光动力处理后的生物膜中的细菌细胞膜受到损伤，而扫描电子显微镜（SEM）证实了光动力疗法处理后的生物膜被破坏。
