Study of the Effect of Low-Intensity Currents Without External Power Sources on Planktonic Cells of Multidrug-Resistant Pseudomonas aeruginosa Strains and Their Susceptibility to Antibiotics

Annotation. The global threat of bacterial resistance to antibiotics necessitates the search for alternatives and methods to overcome resistance. The aim of this study was to investigate the antibacterial effect of low-intensity electric current on multidrug-resistant P. aeruginosa strains and to determine its impact on bacterial susceptibility to antibiotics. The effect of electric current was studied on reference and clinical multidrug-resistant strains of P. aeruginosa (n=15) in isotonic solution and meat-peptone broth (MPB), with bacterial concentration measured using a densitometer. The susceptibility of P. aeruginosa to antibiotics after exposure to the physical factor was assessed using the serial dilution method to determine the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC). The arithmetic mean (M), standard error of the mean (m), and statistical significance (p) were calculated. As a result of electric current exposure on clinical P. aeruginosa strains in isotonic solution, a significant reduction in bacterial concentration was observed compared to the untreated control: a 1.3-fold decrease at 24 hours (p≤0.05) and a 2.38-fold decrease at 48 hours (p≤0.01). In MPB conditions, the electric current led to a significant reduction in P. aeruginosa cell concentration by 1.36-fold (p ≤ 0.05) at 24 hours and by 1.42-fold (p≤0.05) at 48 hours. The treatment with electric current reduced the antibiotic resistance of the studied strains by 2- to 4-fold. Without prior electric current exposure, the average MIC values for ceftazidime were 156.25±31.25 µg/mL, and MBC - 479.17±122.55 µg/mL. For cefepime, MIC and MBC values were 187.5±68.47 µg/mL and 520.83±159.48 µg/mL, respectively. The average MIC of ceftazidime significantly decreased (p≤0.001) by approximately 2.67-fold, and MBC by 3.33-fold. The average MIC of cefepime significantly decreased (p≤0.001) by 3.67-fold, and MBC by 4.67-fold. The reduction in antibiotic MIC values for resistant P. aeruginosa strains under the influence of low-intensity electric currents expands the understanding of the potential use of this physical factor to weaken the adaptive properties of P. aeruginosa and provides additional opportunities for combating this pathogen responsible for infectious complications.