Pourhajibagher Maryam, Mahmoudi Hassan, Rezaei-Soufi Loghman, Alikhani Mohammad Yousef, Bahador Abbas
Dental Research Center, Dentistry Research Institute, Tehran University of Medical Sciences, Tehran, Iran.
Microbiology Department, Hamadan University of Medical Sciences, Hamadan, Iran.
Photodiagnosis Photodyn Ther. 2020 Jun;30:101717. doi: 10.1016/j.pdpdt.2020.101717. Epub 2020 Mar 9.
As the increase in the prevalence of antimicrobial resistant bacterial strains, development of adjuvant antimicrobial approach for the treatment of burn wound infection is important. Therefore, the aim of this study was to assess the effectiveness of antimicrobial photodynamic therapy (aPDT) using indocyanine green (ICG) in reducing the bacterial load and expression profiling of the quorum sensing (QS) system associated with the biofilm formation in multi-species bacterial biofilms.
Multi-species bacterial suspension including Acinetobacter baumannii, Pseudomonas aeruginosa, and Staphylococcus aureus were photosensitized with ICG, which was excited at a wavelength of 810 nm. After evaluating the dose of ICG-aPDT contributing to the sub-significant reduction of colony forming unit (CFU)/mL, the gene expression levels of abaI, agrA, and lasI were assessed using real-time quantitative reverse transcription polymerase chain reaction. As well as, lipid peroxidation, superoxide radicals and reactive oxygen species (ROS) were measured and the morphological changes of multi-species bacteria were evaluated by scanning electron microscopy (SEM).
According to the results, maximal sub-significant reduction dose of aPDT against CFUs/mL of multi-species bacterial cells was found with a combination of 31.2 μg/mL of ICG and irradiation by the diode laser for 1 min, with an estimated average output light energy 31.2 J/cm. The expression levels of abaI, agrA, and lasI in A. baumannii, P. aeruginosa, and S. aureus were down-regulated to approximately 1.9-, 3.7-, and 4.9-fold, respectively. The amount of lipid peroxidation, superoxide radical production, and ROS generation significantly increased (P < 0.05). Also, the cell morphology under SEM showed that ICG-aPDT is a stressful condition for multi-species bacterial cells.
ICG-aPDT with antimicrobial, anti-biofilm, and gene expression inhibitor characteristics, as well as, ROS generation can be used for the treatment of burn wound infections in vivo.
随着抗菌耐药菌株的流行率增加，开发用于治疗烧伤创面感染的辅助抗菌方法很重要。因此，本研究的目的是评估使用吲哚菁绿（ICG）的抗菌光动力疗法（aPDT）在降低多物种细菌生物膜中与生物膜形成相关的群体感应（QS）系统的细菌载量和表达谱方面的有效性。
用ICG对包括鲍曼不动杆菌、铜绿假单胞菌和金黄色葡萄球菌在内的多物种细菌悬液进行光敏化处理，ICG在810 nm波长下激发。在评估有助于显著降低菌落形成单位（CFU）/mL的ICG-aPDT剂量后，使用实时定量逆转录聚合酶链反应评估abaI、agrA和lasI的基因表达水平。此外，测量脂质过氧化、超氧自由基和活性氧（ROS），并通过扫描电子显微镜（SEM）评估多物种细菌的形态变化。
根据结果，发现aPDT对多物种细菌细胞CFUs/mL的最大显著降低剂量是31.2 μg/mL的ICG与二极管激光照射1分钟的组合，估计平均输出光能为31.2 J/cm。鲍曼不动杆菌、铜绿假单胞菌和金黄色葡萄球菌中abaI、agrA和lasI的表达水平分别下调至约1.9倍、3.7倍和4.9倍。脂质过氧化、超氧自由基产生和ROS生成量显著增加（P<0.05）。此外，SEM下的细胞形态表明ICG-aPDT对多物种细菌细胞是一种应激条件。
具有抗菌、抗生物膜和基因表达抑制特性以及ROS生成的ICG-aPDT可用于体内烧伤创面感染的治疗。
