Effect of Extremely Low-Frequency Pulsed Electromagnetic Field Intensity and Exposure Time on Pseudomonas aeruginosa:...

Pulsed electromagnetic fields (PEMFs) may exert antimicrobial effects, which could be relevant both in medical applications and as a contributing factor in electro-disinfection processes. This study was designed to evaluate their impact on the viability of Pseudomonas aeruginosa (ATCC 27853). Experiments were performed in three independent biological replicates, each with three technical replicates per group. Groups 1-3 served as controls and were not exposed to PEMFs. Groups 4-6, 7-9, and 10-12 were exposed to PEMFs of 40, 60, and 80 µT, respectively, for 4, 8, and 24 h using a cylindrical copper solenoid coil. Bacterial viability was assessed via colony-forming unit (CFU) counts, and log₁₀ CFU/mL values were reported. Transmission electron microscopy (TEM) was used to examine structural changes in bacterial cells. PEMF exposure significantly reduced P. aeruginosa viability, with magnetic field strength (p < 0.001), exposure time (p < 0.01), and their interaction (p < 0.05) showing significant effects. Post hoc analysis revealed that higher field strengths, particularly 80 µT after 24 h, produced the greatest reduction in CFU counts, whereas 40 µT showed no significant difference compared to controls (p > 0.05). TEM images demonstrated pronounced degeneration and structural damage in PEMF-exposed bacterial cells. PEMF exposure reduced CFU counts in an intensity and duration-dependent manner. While a dose-related trend is suggested, limited experimental conditions preclude definitive conclusions, and findings should be interpreted cautiously due to the in vitro design.