Background: The radiation emitted from electromagnetic fields (EMF) can cause biological effects on prokaryotic and eukaryotic cells, including non-thermal effects.
Objective: The present study evaluated the non-thermal effects of wireless fidelity (Wi-Fi) operating at 2.4 GHz part of non-ionizing EMF on different pathogenic bacterial strains (Escherichia coli 0157H7, Staphylococcus aureus, and Staphylococcus epidermis). Antibiotic resistance, motility, metabolic activity and biofilm formation were examined.
Material and Methods: In this case-control study, a Wi-Fi router was used as a source of microwaves and also bacterial cells were exposed to Wi-Fi radiation continuously for 24 and 48 hours. The antibiotic susceptibility was carried out using a disc diffusion method on Müller Hinton agar plates. Motility of Escherichia coli 0157H7 was conducted on motility agar plates. Cell metabolic activity and biofilm formation were performed using 3-(4, 5-Dimethylthiazol-2yl)-2, 5-diphenyltetrazolium bromide (MTT) assay and crystal violet quantification, respectively. Results: The exposure to Wi-Fi radiation altered motility and antibiotic susceptibility of Escherichia coli 0157H7. However, there was no effect Wi-Fi radiation on antibiotic susceptibility of Staphylococcus aureus and Staphylococcus epidermis. On the other hand, the exposed cells, as compared to the unexposed control, showed an increased metabolic activity and biofilm formation ability in Escherichia coli 0157H7, Staphylococcus aureus and Staphylococcus epidermis. Conclusion: These results proposed that Wi-Fi exposure acted on bacteria in stressful manner by increasing antibiotic resistance and motility of Escherichia coli 0157H7, as well as enhancing biofilm formation by Escherichia coli 0157H7, Staphylococcus aureus and Staphylococcus epidermis. The findings may have implications for the management of serious diseases caused by these infectious bacteria.