CC BY
4*
ALT'23
The 30th International Conference on Advanced Laser Technologies
B-P-10
Sensitivity of clinical strain of Staphylococcus aureus to photody-namic action using pyridylporphyrins
T. V. Sharabarina1, M. V. Korchenova1, E. S. Tuchina1, L. V. Mkrtchyan2, A. A. Zakoyan2, O. A. Ino-
zemtseva1, G. V. Gyulkhandanyan2, V. V. Tuchin1
'Saratov State University, 410012, Russia, Saratov, Astrakhanskaya, 83 2Institute of Biochemistry, NAS of Armenia, 0014, Armenia, Yerevan, P. Sevak st., 5/1
Currently, the problem of excessive and improper use of antibiotics for prevention and self-treatment is more acute than ever, which in turn leads to the emergence of new antibiotic-resistant strains of bacteria. Clinical strains of Staphylococcus aureus are most important pathogens causing severe nosocomial infections. In modern medicine, antimicrobial photodynamic action is an alternative way to combat diseases caused by both susceptible and resistant bacteria. In this regard, the main goal was to study new porphyrin compounds in low concentrations as promising photosensitizers in the antimicrobial photodynamic effect on staphylococci.
The clinical strain of S. aureus was used as the studied microorganisms and was grown at a temperature of 37°C on a universal nutrient medium.
An LED with a maximum emission spectrum of ^=405 nm and a power density of 80 mW/cm2 was used as a radiation source. In all experiments, the radiation mode was continuous. Irradiation time varied from 5 to 30 min.
Water-soluble meso-substituted cationic pyridylporphyrins and their zinc derivatives (PPhI-TOEt4PyP; PPhII-Zn-TBut3PyP; PPhIII-Zn-TOEt4PyP) with various peripheral functional groups were used as a photosensitizer in concentration 0,03 ^g/ml.
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Time of irradiation, min □ 405 nm HH 405 nm + PPhI 0,03 1=1405 nm + PPhll 0,03 □ 405 nm + PPhlll 0,03
Fig.1. Change in quantity of clinical S. aureus strain under photodynamic action of blue (405 nm) LED radiation and pyridylporphyrins
Radiation with a wavelength of 405 nm did not affect the growth of tested S. aureus strain. After 30 minutes of exposure survival remained within 6,4-5,2 lgCFU/ml (Fig.1, black). After 10 min of irradiation there was a decrease in the bacterial population of S. aureus by 2,6 lgCFU/ml after treatment with PPhI (Fig.1, strips), by 1,8 lgCFU/ml after treatment with PPhll (Fig. 1, gray) and by 2,7 lgCFU/ml after treatment with PPhlll (Fig.1, dots). Increasing the irradiation time to 30 min led to the death of bacterial cells of S. aureus clinical strain by 3,5-4,6 lgCFU/ml. The maximum decrease in survival (by 4,6 lgCFU/ml) was demonstrated by the sample containing PPhlll.
Thus, it was found that the studied porphyrins at low concentrations are promising photosensitizers for antimicrobial photodynamic therapy of studied S. aureus clinical strain. Our studies revealed that PPhlll is the most effective of the studied porphyrins under 30 min 405 nm LED continuous radiation mode.
