Group of Advanced Oxidation Procedures, Swiss Federal Institute of Technology, EPFL-SB- ISIC-GPAO, Station 6, CH-1015 Lausanne, Switzerland; Department of Fundamental Microbiology, University of Lausanne, Quartier Unil-Sorge, Biophore Building, CH-1015 Lausanne, Switzerland.
Group of Advanced Oxidation Procedures, Swiss Federal Institute of Technology, EPFL-SB- ISIC-GPAO, Station 6, CH-1015 Lausanne, Switzerland.
J Photochem Photobiol B. 2017 Sep;174:229-234. doi: 10.1016/j.jphotobiol.2017.07.030. Epub 2017 Jul 29.
Candida spp. are able to survive on hospital surfaces and causes healthcare-associated infections (HCAIs). Since surface cleaning and disinfecting interventions are not totally effective to eliminate Candida spp., new approaches should be devised. Copper (Cu) has widely recognized antifungal activity and the use of Cu-sputtered surfaces has recently been proposed to curb the spread of HCAIs. Moreover, the activity of Cu under the action of actinic light remains underexplored. We investigated the antifungal activity of Cu-sputtered polyester surfaces (Cu-PES) against azole-resistant Candida albicans and Candida glabrata under dark and low intensity visible light irradiation (4.65mW/cm). The surface properties of Cu-PES photocatalysts were characterized by diffuse reflectance spectroscopy (DRS) and X-ray fluorescence (XRF). Under dark, Cu-PES showed a fungicidal activity (≥3logCFU reduction of the initial inoculum) against both C. albicans DSY296 and C. glabrata DSY565 leading to a reduction of the starting inoculum of 3.1 and 3.0logCFU, respectively, within 60min of exposure. Under low intensity visible light irradiation, Cu-PES exhibited an accelerated fungicidal activity against both strains with a reduction of 3.0 and 3.4logCFU, respectively, within 30min of exposure. This effect was likely due to the semiconductor CuO/CuO charge separation. The decrease in cell viability of the two Candida strains under dark and light conditions correlated with the progressive loss of membrane integrity. These results indicate that Cu-PES represent a promising strategy for decreasing the colonization of surfaces by yeasts and that actinic light can improve its self-disinfecting activity.
假丝酵母属能够在医院表面存活，并引起与医疗保健相关的感染（HCIA）。由于表面清洁和消毒干预措施并不能完全有效地消除假丝酵母属，因此需要设计新的方法。铜（Cu）具有广泛认可的抗真菌活性，最近已经提出使用镀铜表面来抑制 HCIA 的传播。此外，Cu 在光激活作用下的活性仍未得到充分探索。我们研究了镀铜聚酯表面（Cu-PES）在黑暗和低强度可见光照射（4.65mW/cm）下对唑类耐药白假丝酵母菌和光滑假丝酵母菌的抗真菌活性。Cu-PES 光催化剂的表面特性通过漫反射光谱（DRS）和 X 射线荧光（XRF）进行了表征。在黑暗中，Cu-PES 对 C. albicans DSY296 和 C. glabrata DSY565 均表现出杀菌活性（初始接种物减少≥3logCFU），分别导致起始接种物减少 3.1 和 3.0logCFU，暴露 60 分钟内。在低强度可见光照射下，Cu-PES 对两种菌株均表现出加速杀菌活性，暴露 30 分钟内分别减少 3.0 和 3.4logCFU。这种效果可能是由于半导体 CuO/CuO 的电荷分离。在黑暗和光照条件下，两种假丝酵母菌株的细胞活力下降与膜完整性的逐渐丧失相关。这些结果表明，Cu-PES 是减少表面酵母定植的一种很有前途的策略，而光激活可以提高其自我消毒活性。
