ABSTRACT
Background: Electromagnetic non-ionizing radiation has both thermal and non-thermal outcomes on biological systems, such as humans, animals, and bacteria. Objective: This study aimed to investigate the effect of non-ionizing radiofrequency radiation, emitted by Wi-Fi routers, on bacterial strains and the modification of their susceptibility to modern antibiotics. Material and Methods: In this case-control paired study, four bacteria were selected, and one colony from each bacterial strain was exposed to Wi-Fi radiation forming the exposure group. Another set of colonies was not exposed to Wi-Fi radiation, forming the control group. Eight different antibiotic disks were set on the bacterial plates, and the inhibition zone was measured every 3 h for each colony. Results: Electromagnetic radiation affects bacterial colonies and their susceptibility to antibiotics. Analysis revealed statistically significant differences, correlated with the bacterial strain, the antibiotic agent, and the time of the exposure, in the inhibition zones, mostly after 6 and 24 h (p-value < 0.05). Conclusion: A correlation was observed between antibiotic susceptibility and non-ionizing radiofrequency exposure. Studying the effects of radiofrequency radiation on prokaryotic organisms could clarify more complicated cell structures and organisms, such as eukaryotic. Further experiments, in vitro and in vivo, could provide more information about these outcomes and cause experts to discuss the current guidelines of exposure limits.
ABSTRACT
BACKGROUND: Antibiotic management of low-virulent implant-associated infections induced by Cutibacterium acnes may be compromised by multi-drug resistance development, side effects, and increased cost. Therefore, we sought to assess the effects of shock wave therapy against the above pathogen using an in vitro model of infection. METHODS: We used a total of 120 roughened titanium alloy disks, simulating orthopedic biomaterials, to assess the results of radial extracorporeal shock wave therapy (rESWT) against C. acnes (ATCC 11827) biofilms relative to untreated control. In particular, we considered 1.6 to 2.5 Bar with a frequency ranging from 8-11 Hz and 95 to 143 impulses per disk to investigate the antibacterial effect of rESWT against C. acnes planktonic (free-floating) and biofilm forms. RESULTS: Planktonic bacteria load diminished by 54% compared to untreated control after a 1.8-bar setting with a frequency of 8 Hz and 95 impulses was applied (median absorbance (MA) for intervention vs. control groups was 0.9245 (IQR= 0.888 to 0.104) vs. 0.7705 (IQR = 0.712 to 0.864), respectively, p = 0.001). Likewise, a statistically significant reduction in the amount of biofilm relative to untreated control was documented when the above setting was considered (MA for treatment vs biofilm control groups was 0.244 (IQR= 0.215-0.282) and 0.298 (IQR = 0.247-0.307), respectively, p = 0.033). CONCLUSION: A 50% biofilm eradication was documented following application of low-pressure and low-frequency radial shock waves, so rESWT could be investigated as an adjuvant treatment to antibiotics, but it cannot be recommended as a standalone treatment against device-associated infections induced by C. ances.
