Application of photodynamic inactivation against urinary tract bacteria
Nadezhda I. Ignatova, Vadim V. Elagin V, Ivan A. Budruev, Artem E. Antonyan, Olga S. Streltsova, Vladislav A. Kamensky
Privolzhsky Research Medical University, Nizhny Novgorod, Russia
Abstract
Uropathogenic microorganisms are the cause of the urinary tract inflammatory diseases and urolithiasis, and can also be found in the urine asymptomatically in 20% of cases. E.coli, P.mirabilis, and E.faecalis are common multidrug-resistant uropathogens. Photodynamic inactivation (PDI) is an alternative to antibiotic therapy method for biocidal action against microorganisms, which can be used for lithotripsy and sanitation of the bladder cavities.
The purpose of the study was to select the parameters for PDI against uropathogenic microorganisms.
Bacterial strains used in the study were isolated from urine samples of patients. The sensitivity of uropathogenic microorganisms to PDI was studied on pure cultures and in native urine. The photosensitizer was used in the work, as well as Triton X-100 was applying to increase the permeability of the cell wall of gram-negative microorganisms. The samples were irradiated by a medical laser with a wavelength of 662 nm.
50 strains of uropathogens belonging to 18 species were isolated from 36 samples of native urine. Among them, the most common were Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumoniae. The value of logarithmic decrease in CFU for gram-positive bacteria ranged from 5 to 6, which corresponds to inactivation 99.999-99.9999% of bacterial cells in a sample. For gram-negative strains, this value was slightly lower and ranged from 4 to 5.5, which, nevertheless, corresponds to inactivation 99.99-99.999% of CFU bacteria. The addition of Triton X-100 increase the efficiency from 46% to 99.99% for E. coli, from 99% to 99.99% for P. mirabilis, from 16% to 94% for K. pneumoniae and from 97% to 99.999% for P. aeruginosa It should be noted that the PDI was affect microorganisms both in isolated pure cultures and in native urine.
Thus, photodynamic inactivation may be considered as an alternative to antibiotic therapy method of biocidal action against uropathogenic microorganisms.
The study was supported by the Russian Science Foundation under grant No. 21-15-00371.
Speaker
Vadim Elagin
Privolzhsky Research Medical University
Russia
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