Antimicrobial action of low-intensity laser radiation and methylene blue on some opportunistic microorganisms

Abstract

Overuse and misuse of antibiotics has led to the emergence and massive spread of resistant microorganisms. As a result, the study of antimicrobial properties of non-medicinal agents, in particular photodynamic therapy, is relevant. The aim of the work was to study the antimicrobial activity of the complex effect of the photosensitizer methylene blue and low-intensity laser radiation of the red spectrum on some opportunistic microorganisms. To study the complex effect of methylene blue and laser radiation with a wavelength of 660 nm, the studied microorganisms were divided into 4 groups: control group; 2nd group that was treated only with laser radiation; group 3 – to which photosensitizer was added and group 4 to which photosensitizer was added with subsequent irradiation. The degree of influence of these factors was determined by counting the number of microbial colonies after inoculation into solid nutrient media in Petri dishes. The objects of the study are strains of Staphylococcus aureus, Escherichia coli and Candida albicans isolated from the periodontal pockets of patients with chronic generalized periodontitis. It was established that low-intensity laser radiation has a certain stimulating effect on the studied objects, which was manifested in an increase in the intensity of the growth of microorganisms by 10-37%, compared to the control. The number of colonies of group 3 microorganisms decreased on average by 10-54%. The most pronounced antimicrobial effect was observed with the combined use of methylene blue and laser radiation. In this case the intensity of growth of microorganisms decreased by 26-77%. Thus, low-intensity laser radiation in combination with methylene blue has pronounced antimicrobial activity against the studied strains of microorganisms. The greatest antimicrobial activity was noted against C. albicans. The obtained results can be used in the treatment of diseases of periodontal tissues, in particular, the rehabilitation of periodontal pockets.