Susceptibility of bacterial species commonly found in abdominal abscesses to low-dose photodynamic therapy: Effects of methylene blue concentration, fluence rate, and fluence.

IF 2.6 4区 生物学 Q3 BIOCHEMISTRY & MOLECULAR BIOLOGY
Darrian S Hawryluk, Martin S Pavelka, Timothy M Baran
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Abstract

The objective of this study was to determine the effects of methylene blue (MB) concentration, laser fluence rate, and laser fluence on the efficacy of in vitro photodynamic therapy (PDT) for four bacteria commonly found in human abscesses. PDT experiments were performed with four of the most common bacteria found in abdominal abscesses: Escherichia coli, Enterococcus faecalis, Staphylococcus aureus, and Pseudomonas aeruginosa. MB concentration was varied from 50 to 300 μg/mL, and the laser fluence rate was varied from 1 to 4 mW/cm2 at a fluence of 7.2 J/cm2. Higher fluence rates and fluences were explored for P. aeruginosa. Primary outcomes were the reduction in colony-forming units (CFU) following PDT and measured MB uptake following drug incubation. Gram-positive bacteria (E. faecalis and S. aureus) were eradicated at all MB concentrations and laser fluence rates tested. Efficacy was reduced for E. coli but still resulted in >6 log10 reduction in CFU when MB concentration was at least 100 μg/mL. P. aeruginosa required higher fluence (28.8 J/cm2) to achieve comparable efficacy, while increasing fluence rate did not have a significant effect on PDT efficacy. MB uptake was reduced in Gram-negative species compared to Gram-positive species, particularly P. aeruginosa, although uptake was not significantly correlated with CFU reduction. Gram-positive bacteria can be eradicated in vitro with low levels of MB (50 μg/mL), laser fluence (7.2 J/cm2), and laser fluence rate (1 mW/cm2). E. coli showed substantial cell killing (>6 log10 CFU reduction) with these same parameters. Low MB uptake and PDT efficacy in P. aeruginosa could be overcome by increasing the laser fluence, while increasing fluence rate did not have an effect.

常见于腹部脓肿的细菌种类对低剂量光动力治疗的敏感性:亚甲蓝浓度、通量和通量的影响
本研究的目的是确定亚甲基蓝(MB)浓度、激光影响率和激光影响对体外光动力治疗(PDT)对人类脓肿中常见的四种细菌的疗效的影响。PDT实验用腹部脓肿中最常见的四种细菌进行:大肠杆菌、粪肠球菌、金黄色葡萄球菌和铜绿假单胞菌。MB浓度为50 ~ 300 μg/mL,激光辐照强度为1 ~ 4 mW/cm2,辐照强度为7.2 J/cm2。探索了铜绿假单胞菌更高的影响率和影响。主要结果是PDT后菌落形成单位(CFU)的减少和药物孵育后MB摄取的测量。革兰氏阳性菌(粪球菌和金黄色葡萄球菌)在所有MB浓度和激光影响率下被根除。当MB浓度≥100 μg/mL时,对大肠杆菌的药效降低,但CFU仍可降低bb60 log10。P. aeruginosa需要更高的影响(28.8 J/cm2)才能达到相当的疗效,而提高影响率对PDT疗效没有显著影响。与革兰氏阳性菌相比,革兰氏阴性菌的MB摄取减少,尤其是铜绿假单胞菌,尽管摄取与CFU减少没有显著相关。低MB浓度(50 μg/mL)、低激光浓度(7.2 J/cm2)、低激光浓度(1 mW/cm2)均可在体外杀灭革兰氏阳性菌。在相同的参数下,大肠杆菌显示出大量的细胞杀伤(CFU减少60 log10)。提高激光辐照强度可以克服P. aeruginosa对MB的低吸收和PDT的低效率,而提高辐照强度则没有效果。
本文章由计算机程序翻译,如有差异,请以英文原文为准。
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来源期刊
Photochemistry and Photobiology
Photochemistry and Photobiology 生物-生化与分子生物学
CiteScore
6.70
自引率
12.10%
发文量
171
审稿时长
2.7 months
期刊介绍: Photochemistry and Photobiology publishes original research articles and reviews on current topics in photoscience. Topics span from the primary interaction of light with molecules, cells, and tissue to the subsequent biological responses, representing disciplinary and interdisciplinary research in the fields of chemistry, physics, biology, and medicine. Photochemistry and Photobiology is the official journal of the American Society for Photobiology.
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