In vitro Evaluation of Antimicrobial Photodynamic Effect of Riboflavin against Multi-Drug Resistant Pseudomonas aeruginosaisolates

Background and Objectives: The phenomenon of antibiotic resistance is an important medical issue worldwide. One of the bacterial pathogens that is of major epidemiological importance among nosocomial infections is Pseudomonas aeruginosa. Due to the increase in multidrug-resistant strains of Pseudomonas aeruginosa, the need for new antibiotics or other therapies may be needed. The development of alternative and supportive therapies with different mechanisms of action than antibiotics such as pharmacotherapy, nanoparticles, photodynamic therapy is of great importance. The PDT mechanism consists of three components of low-light visible light at a specific wavelength (380 to 750 nm), photosynthesizer and oxygen. Photosynthesis is a compound capable of binding to target cells or bacteria that has a strong optical absorption during visible wavelength and is capable of producing a triple quantum product. In this study, the photosensitizer riboflavin is used for photodynamic therapy. For this purpose, the bacterial isolate will be exposed to visible light (420 to 480 nm) at times of 30, 90 and 120 seconds, with final concentrations of riboflavin containing 10.50 and 100 μmol per liter Materials and Methods: Drop 100 microliters of bacterial suspension at half McFarland concentration in 96 well wells. Add 100 microliters of photosensitizer to the test wells to obtain a final concentration of 10, 50 and 100 μmol per liter. Allow the microplate to stand at room temperature for 10 minutes in dark conditions, and then individually exposed to LED light for 30 seconds, 90 seconds, and 120 seconds. Two control samples will also be used to investigate the effect of light alone, photosynthesis alone on bacterial growth. Then remove all 200 μl of suspension in all treated and untreated wells and dilute using normal saline. Then, 10 μL of each dilution was cultured on Müller Hinton agar medium and after 24 h incubation at 37 ° C, bacterial count was determined by applying dilution coefficients in each well in CFU / ml. . Finally, the number of bacteria in all test and control groups will be calculated and their growth rate will be evaluated by percent reduction criterion. As shown in the table, the percentage of each treatment decreases in the desired concentration and under the time of light irradiation are given separately in the table.Conclution: Although photodynamic therapy is not yet widely used in the treatment of patients in bed, due to the increasing antibiotic resistance in bacteria, and especially in Pseudomonas strains, this method can be a very good alternative for reducing antibiotic resistance and patient treatment, especially since the method is very simple, inexpensive and affordable and the riboflavin material is completely safe. In this method riboflavin is used at very low concentrations and visible light and two factors of riboflavin concentration and time of light irradiation are essential in this method. As shown in the results, a significant decrease in the number of bacteria was observed with the increase of riboflavin concentration and the time of light irradiation, compared to the control group. The results of this study show that Jade methods such as photodynamic therapy can be very effective in the treatment of patients, especially in patients with superficial ulcers such as burn wounds.