Department of Biotechnology, University of Rijeka, Rijeka, Croatia.
Department of Microbiology and Parasitology, Faculty of Medicine, University of Rijeka, Rijeka, Croatia.
PLoS One. 2023 Aug 15;18(8):e0290080. doi: 10.1371/journal.pone.0290080. eCollection 2023.
There is an increasing need to discover effective methods for treating municipal wastewater and addressing the threat of multidrug-resistant (MDR) strains of bacteria spreading into the environment and drinking water. Photodynamic inactivation (PDI) that combines a photosensitiser and light in the presence of oxygen to generate singlet oxygen and other reactive species, which in turn react with a range of biomolecules, including the oxidation of bacterial genetic material, may be a way to stop the spread of antibiotic-resistant genes. The effect of 5,10,15,20-(pyridinium-3-yl)porphyrin tetrachloride (TMPyP3) without light, and after activation with violet-blue light (VBL) (394 nm; 20 mW/cm2), on MDR strains of Pseudomonas aeruginosa, Klebsiella pneumoniae and K. pneumoniae OXA-48 in tap water and municipal wastewater was investigated. High toxicity (~2 μM) of TMPyP3 was shown in the dark on both strains of K. pneumoniae in tap water, while on P. aeruginosa toxicity in the dark was low (50 μM) and the PDI effect was significant (1.562 μM). However, in wastewater, the toxicity of TMPyP3 without photoactivation was much lower (12.5-100 μM), and the PDI effect was significant for all three bacterial strains, already after 10 min of irradiation with VBL (1.562-6.25 μM). In the same concentrations, or even lower, an anti-adhesion effect was shown, suggesting the possibility of application in biofilm control. By studying the kinetics of photoinactivation, it was found that with 1,562 μM of TMPyP3 it is possible to achieve the complete destruction of all three bacteria after 60 min of irradiation with VBL. This study confirmed the importance of studying the impact of water constituents on the properties and PDI effect of the applied photosensitiser, as well as checking the sensitivity of targeted bacteria to light of a certain wavelength, in conditions as close as possible to those in the intended application, to adjust all parameters and perfect the method.
目前，人们越来越需要发现有效的方法来处理城市污水，并解决多药耐药（MDR）细菌菌株扩散到环境和饮用水中的威胁。光动力灭活（PDI）是一种将光敏剂与氧气结合，在光照下产生单线态氧和其他活性物质的方法，这些活性物质会与一系列生物分子发生反应，包括细菌遗传物质的氧化，这可能是阻止抗生素耐药基因传播的一种方法。研究了 5,10,15,20-（吡啶-3-基）卟啉四氯（TMPyP3）在没有光照和用紫蓝光（VBL）（394nm；20mW/cm2）激活后的，对自来水中的铜绿假单胞菌、肺炎克雷伯菌和产酸克雷伯氏菌 OXA-48 等 MDR 菌株的影响。在自来水中，TMPyP3 在黑暗中对两种肺炎克雷伯菌的毒性很高（~2μM），而在黑暗中对铜绿假单胞菌的毒性较低（50μM），但 PDI 效果显著（1.562μM）。然而，在废水中，未经光活化的 TMPyP3 的毒性要低得多（12.5-100μM），并且 PDI 效应在所有三种细菌菌株中都很显著，甚至在 VBL 照射 10 分钟后（1.562-6.25μM）。在相同的浓度下，甚至更低，也表现出了抗粘附作用，这表明该方法有可能应用于生物膜控制。通过研究光灭活动力学，发现使用 1.562μM 的 TMPyP3，在 VBL 照射 60 分钟后，可以完全破坏所有三种细菌。本研究证实了在尽可能接近预期应用条件下，研究水成分对应用的光敏剂的性质和 PDI 效应的影响，以及检查目标细菌对特定波长光的敏感性的重要性，以便调整所有参数并完善该方法。
