IMPACT OF POLARIZED LOW-INTENSE RADIATION AND PHOTOSENSITIZERS ON GROWTH OF Staphylococcus aureus

Abstract

Drug resistance occurrence and spread is a global and unsolved healthcare concern that leads to the increased morbidity and mortality in hospitals, time of hospitalization, and huge financial loss. Due to this, the investigation of novel approaches to combat microorganisms is of great relevance. One of such approach is the use of non-medicamentous means, one of which is antimicrobial photodynamic therapy. Latter involves the use of low power radiation with appropriate wavelength treated with a photosensitizer, which results in the generation of reactive oxygen species that kill bacteria unselectively via an oxidative burst. The peculiarity of the method is the effect on numerous structures of the bacterial cell, as a result of which the probability of developing resistance by microorganisms is low. The purpose of the study was to investigate combine impact of polarized incoherent low-energy radiation with different wavelengths and photosensitizers on growth rate of Staphylococcus aureus. We studied direct impact of polarized light with different light filters (second group), photosensitizers –methylene blue, brilliant green, malachite green, methylene green, azure, crystal violet, fuchsin, and chrysoidin (third group), and complex of these factors (fourth group) on growth rate of clinical strain of Staphylococcus aureus and collection test strain Staphylococcus aureus ATCC 25923 on solid nutrient media. The results were determined by counting the number of bacterial colonies on Petri dishes after 24 hours of incubation in a thermostat at 37 ℃ and comparedwith the first (control) group, which was affected by neither irradiation nor photosensitizers nor their complex. The absorption spectra of photosensitizers were determined spectrophotometrically in the range of 200-1000 nm. It is established that irradiation of the studied strains with polarized radiation causes a slight decrease in the intensity of their growth. Photosensitizers reduced the number of bacterial colonies on Petri dishes by 16-42.5% compared with controls. The complex effect of photosensitizers and polarized radiation caused a decrease in the growth rate of microorganisms by 22.4-62.5%. The most pronounced antimicrobial effect was observed when using methylene blue and red spectrum, as well as gentian violet and yellow spectrum. It should be noted that the complex effect of photosensitizers and polarized radiation led to an average of 10- 45% more pronounced decrease in the growth rate of the studied microorganisms of the fourth group, compared with only photosensitizers for microorganisms of the third group. The results obtained can be used in the treatment of purulent-inflammatory processes caused by Staphylococcus aureus, in particular periodontal diseases.