Evaluation of the Effect of Radiofrequency Radiation Emitted From Wi-Fi Router and Mobile Phone Simulator on the Antibacterial Susceptibility of Pathogenic Bacteria Listeria monocytogenes and Escherichia coli

Interactions between electromagnetic radiation and biological systems

Even though the bioeffects of electromagnetic radiation (EMR) have been extensively investigated during the past several decades, our understandings of the bioeffects of EMR and the mechanisms of the interactions between the biological systems and the EMRs are still far from satisfactory. In this article, we introduce and summarize the consensus, controversy, limitations, and unsolved issues. The published works have investigated the EMR effects on different biological systems including humans, animals, cells, and biochemical reactions. Alternative methodologies also include dielectric spectroscopy, detection of bioelectromagnetic emissions, and theoretical predictions. In many studies, the thermal effects of the EMR are not properly controlled or considered. The frequency of the EMR investigated is limited to the commonly used bands, particularly the frequencies of the power line and the wireless communications; far fewer studies were performed for other EMR frequencies. In addition, the bioeffects of the complex EM environment were rarely discussed. In summary, our understanding of the bioeffects of the EMR is quite restrictive and further investigations are needed to answer the unsolved questions.

The effect of exposure to non-ionising radiofrequency field on Escherichia coli, Klebsiella oxytoca and Pseudomonas aeruginosa biofilms

An environment with a higher accumulation of electromagnetic non-ionising radiofrequency (RF) emissions generated by various telecommunication, data transport and navigation devices (mobile phones, Wi-Fi, radar, etc.) may have a major impact on biological systems. This study aimed to evaluate the incidence of an electromagnetic field (EMF) on the development of bacterial biofilm. Quantification of biofilm production was done by using microtiter plate assay. Bacterial isolates of Escherichia coli, Klebsiella oxytoca and Pseudomonas aeruginosa were exposed with EMF of frequencies 1-5 and 2.4 GHz with an exposure time 3 or 24 h, respectively. Exposure of bacteria to EMF produced a statistically significant increase in biofilm production mainly at 1, 2 and 4 GHz, and in contrast, a significant inhibition of biofilm development occurred at frequencies 3 and 5 GHz, both with exception of K. oxytoca and P. aeruginosa. Wi-Fi operating at 2.4 GHz caused biofilm reduction. The results indicate that EMF exposure act on bacteria in both ways, depending on the frequency: as stressful by enhancing bacterial biofilm formation (under environmental stress, bacteria produce a polysaccharide matrix and aggregate to form biofilms to increase virulence and resistance), although some frequencies leading to biofilm damage could be caused by changes to the physicochemical properties of bacteria.

Electromagnetic fields - do they pose a cardiovascular risk?

Mobile wireless communication technologies have now become an everyday part of our lives, 24 hours a day, 7 days a week. Monitoring the autonomous system under exposition to electromagnetic fields may play an important role in broading of our still limited knowledge on their effect on human body. Thus, we studied the interaction of the high frequency electromagnetic field (HF EMF) with living body and its effect on the autonomic control of heart rate using Heart Rate Variability (HRV) linear and nonlinear analyses in healthy volunteers. A group of young healthy probands (n=30, age mean: 24.2 ± 3.5 years) without any symptoms of disease was exposed to EMF with f=2400 MHz (Wi Fi), and f=2600 MHz (4G) for 5 minutes applied on the chest area. The short-term heart rate variability (HRV) metrics were used as an indicator of complex cardiac autonomic control. The evaluated HRV parameters: RR interval (ms), high frequency spectral power (HF-HRV in [ln(ms2)]) as an index of cardiovagal control, and a symbolic dynamic index of 0V %, indicating cardiac sympathetic activity. The cardiac-linked parasympathetic index HF-HRV was significantly reduced (p =0.036) and sympathetically mediated HRV index 0V % was significantly higher (p=0.002) during EMF exposure at 2400 MHz (Wi-Fi), compared to simulated 4G frequency 2600 MHz. No significant differences were found in the RR intervals. Our results revealed a shift in cardiac autonomic regulation towards sympathetic overactivity and parasympathetic underactivity indexed by HRV parameters during EMF exposure in young healthy persons. It seems that HF EMF exposure results in abnormal complex cardiac autonomic regulatory integrity which may be associated with higher risk of later cardiovascular complications already in healthy probands.

Effects of non-ionizing electromagnetic fields on flora and fauna, Part 2 impacts: how species interact with natural and man-made EMF

Ambient levels of nonionizing electromagnetic fields (EMF) have risen sharply in the last five decades to become a ubiquitous, continuous, biologically active environmental pollutant, even in rural and remote areas. Many species of flora and fauna, because of unique physiologies and habitats, are sensitive to exogenous EMF in ways that surpass human reactivity. This can lead to complex endogenous reactions that are highly variable, largely unseen, and a possible contributing factor in species extinctions, sometimes localized. Non-human magnetoreception mechanisms are explored. Numerous studies across all frequencies and taxa indicate that current low-level anthropogenic EMF can have myriad adverse and synergistic effects, including on orientation and migration, food finding, reproduction, mating, nest and den building, territorial maintenance and defense, and on vitality, longevity and survivorship itself. Effects have been observed in mammals such as bats, cervids, cetaceans, and pinnipeds among others, and on birds, insects, amphibians, reptiles, microbes and many species of flora. Cyto- and geno-toxic effects have long been observed in laboratory research on animal models that can be extrapolated to wildlife. Unusual multi-system mechanisms can come into play with non-human species - including in aquatic environments - that rely on the Earth's natural geomagnetic fields for critical life-sustaining information. Part 2 of this 3-part series includes four online supplement tables of effects seen in animals from both ELF and RFR at vanishingly low intensities. Taken as a whole, this indicates enough information to raise concerns about ambient exposures to nonionizing radiation at ecosystem levels. Wildlife loss is often unseen and undocumented until tipping points are reached. It is time to recognize ambient EMF as a novel form of pollution and develop rules at regulatory agencies that designate air as 'habitat' so EMF can be regulated like other pollutants. Long-term chronic low-level EMF exposure standards, which do not now exist, should be set accordingly for wildlife, and environmental laws should be strictly enforced - a subject explored in Part 3.

Effects of Radiofrequency Electromagnetic Fields Emitted from Mobile Phones and Wi-Fi Router on the Growth Rate and Susceptibility of Enterococcus faecalis to Antibiotics

BACKGROUND

During the last decade, people have been dramatically exposed to radiation emitted from widely-used radiofrequency electromagnetic fields (RF-EMF) generating devices.

OBJECTIVE

This study aimed to evaluate the effects of exposure to RF-EMF emitted from smart phones and Wi-Fi routers on the growth rate and antibiotic sensitivity of Enterococcus faecalis (E. faecalis) as a pathogen in the root canals of teeth.

MATERIAL AND METHODS

In this experimental study, E. faecalis ATCC 19115 was used, characterized and confirmed by morphological and biochemical tests. Antibiotic susceptibility test was measured for several common antibiotics. To perform antibiotic susceptibility tests, disk diffusion (Kirby-Bauer) method on Mueller-Hinton agar plates was used before and after exposure to RF-EMFs emitted from a commercial Wi-Fi router or a mobile phone simulator. Moreover, we measured the optical density at 625 nm after different exposure times using a calibrated UV-visible spectrophotometer to evaluate the effect of RF-EMF exposure on the bacterial growth rate.

RESULTS

Exposure to RF-EMF significantly altered the antimicrobial sensitivity of the E. faecalis. While, the susceptibility of the bacteria decreased significantly after 6 h of exposure, longer exposure time (e.g. exposure for 24 h) increased the susceptibility of the bacteria to all antibiotics. Furthermore, it was found that the bacteria tended to regress to their early state. Moreover, the non-exposed E. faecalis showed a slower growth rate than the bacteria exposed to RF-EMFs.

CONCLUSION

Exposure to RF-EMF emitted by Wi-Fi routers or mobile phone simulator can significantly change the antibiotic susceptibility and growth rate of E. faecalis.

The Effect of Electromagnetic Radiation Transmitted from Routers on Antibiotic Susceptibility of Bacterial Pathogens

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.

Biological Protection in Deep Space Missions

During deep space missions, astronauts are exposed to highly ionizing radiation, incl. neutrons, protons and heavy ions from galactic cosmic rays (GCR), solar wind (SW) and solar energetic particles (SEP). This increase the risks for cancerogenisis, damages in central nervous system (CNS), cardiovascular diseases, etc. Large SEP events can even cause acute radiation syndrome (ARS). Long term manned deep space missions will therefor require unique radiation protection strategies. Since it has been shown that physical shielding alone is not sufficient, this paper propose pre-flight screening of the aspirants for evaluation of their level of adaptive responses. Methods for boosting their immune system, should also be further investigated, and the possibility of using radiation effect modulators are discussed. In this paper, especially, the use of vitamin C as a promising non-toxic, cost-effective, easily available radiation mitigator (which can be used hours after irradiation), is described. Although it has previously been shown that vitamin C can decrease radiation-induced chromosomal damage in rodents, it must be further investigated before any conclusions about its radiation mitigating properties in humans can be concluded.

Biological Effects of a Low-Frequency Electromagnetic Field on Yeast Cells of the Genus Saccharomyces Cerevisiae

Background: Although the scientific community is extensively concerned with the effects of the EMF, the unambiguous explanation of its effects on living structures is still lacking.

Goals: The goal of the study was to evaluate the effect of a low-frequency (LF) electromagnetic field (EMF) on the growth and multiplication of the yeast Saccharomyces cerevisiae.

Methods: Yeast cells were exposed to a frequency of 900 Hz and a magnetic flux density of 2.3 mT. The duration of each experiment was 8 hours, in the beginning of the measurement the value of frequency, rms (root mean square) value of electric current (2 A), and magnetic flux density were fixed set on the exposure device. A paired experiment was performed, a sample exposed to EMF, and a sample shielded from the field. Subsequently, samples were taken every two hours, the number of cells was recorded, and then the concentration of the yeast cells was evaluated at time points. The time points reflected the exposure time of the samples exposed to EMF.

Results: The results indicate that LF EMF at given parameters has an inhibitory effect on the growth and multiplication of yeast cells.

Conclusion: Exposure to EMF can cause the differences in growth dynamics between cells exposed to the field and the unexposed ones.

Effects of Wi-Fi Radiofrequency Radiation on Carbapenem-Resistant Klebsiella pneumoniae

The hazardous consequences of electromagnetic field (EMF) exposure represent a public health concern. Common sources of EMF include smartphones and wireless fidelity (Wi-Fi). The aim of our study is to assess whether exposure to Wi-Fi radiofrequency radiation influences the pathogenic traits of carbapenem-resistant Klebsiella pneumoniae. The susceptibility to antibiotics was evaluated by the determination of minimum inhibitory concentrations (MIC). In this study, K. pneumoniae showed a non-linear response to treatments with Colistin and Gentamycin following different Wi-Fi exposure periods. Transmission electron microscopy revealed morphological changes in the bacterial cell membrane within 24 h of Wi-Fi exposure. Crystal violet quantification and quantitative real-time polymerase chain reaction showed that the ability to form biofilms was greater in Wi-Fi exposed K. pnemoniae when compared to control. Moreover, higher levels of bcsA, mrkA, and luxS messenger RNAs were observed. Our data suggest that Wi-Fi exposure can influence bacteria in a stressful way, leading to an alteration in their antibiotic susceptibility, morphological changes, and cumulative biofilm formation. © 2021 Bioelectromagnetics Society.

Immunity in Space: Prokaryote Adaptations and Immune Response in Microgravity

Immune dysfunction has long been reported by medical professionals regarding astronauts suffering from opportunistic infections both during their time in space and a short period afterwards once back on Earth. Various species of prokaryotes onboard these space missions or cultured in a microgravity analogue exhibit increased virulence, enhanced formation of biofilms, and in some cases develop specific resistance for specific antibiotics. This poses a substantial health hazard to the astronauts confined in constant proximity to any present bacterial pathogens on long space missions with a finite number of resources including antibiotics. Furthermore, some bacteria cultured in microgravity develop phenotypes not seen in Earth gravity conditions, providing novel insights into bacterial evolution and avenues for research. Immune dysfunction caused by exposure to microgravity may increase the chance of bacterial infection. Immune cell stimulation, toll-like receptors and pathogen-associated molecular patterns can all be altered in microgravity and affect immunological crosstalk and response. Production of interleukins and other cytokines can also be altered leading to immune dysfunction when responding to bacterial infection. Stem cell differentiation and immune cell activation and proliferation can also be impaired and altered by the microgravity environment once more adding to immune dysfunction in microgravity. This review elaborates on and contextualises these findings relating to how bacteria can adapt to microgravity and how the immune system subsequently responds to infection.

Effects of GSM 1800 band radiation on composition, structure and bioactivity of exopolysaccharides produced by yoghurt starter cultures

In this study, the effects of GSM 1800 band radiation on composition, structure and bioactivity of exopolysaccharides (EPSs) produced by Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus thermophilus were determined. For this, GSM 1800 band radiation was applied to both cultures and characteristics of EPSs extracted from the control groups (K) and the radiation stressed groups (R) were determined. An alteration in the chemical composition of the EPSs was observed and EPS production levels and molecular weights of the EPSs increased following the GSM 1800 band radiation application. Alterations in the functional groups, thermal and morphological characteristics of EPSs following the GSM 1800 band radiation application were confirmed by FTIR, TGA and SEM analysis, respectively. Importantly no alterations in the antioxidant and antibacterial activity of the EPSs were observed following the radiation application. These results suggested the effects of the GSM radiation on final characteristics of EPSs from yogurt starter cultures.

Exposure to radiofrequency radiation increases the risk of breast cancer: A systematic review and meta-analysis

The present systematic review and meta-analysis investigated the association between exposure to radiofrequency radiation and the risk of breast cancer. The published studies that were available in PubMed, Embase, Cochrane Library, Ovid MEDLINE, CINAHL Plus, Web of Science, Airiti Library, Networked Digital Library of Theses and Dissertations and ProQuest until May 2020 were investigated. A total of eight studies (four case-control and four cohort studies) were eligible for quantitative analysis. A significant association between radiofrequency radiation exposure and breast cancer risk was detected [pooled relative risk (RR)=1.189; 95% confidence interval (CI), 1.056-1.339]. Subgroup analyses indicated that radiofrequency radiation exposure significantly increased the risk of breast cancer susceptibility among subjects aged ≥50 years (RR=2.179; 95% CI, 1.260-3.770). Pooled estimates revealed that the use of electrical appliances, which emit radiofrequency radiation, such as mobile phones and computers, significantly increased breast cancer development (RR=2.057; 95% CI, 1.272-3.327), while occupational radiofrequency exposure and transmitters did not increase breast cancer development (RR=1.274; 95% CI, 0.956-1.697; RR=1.133; 95% CI, 0.987-1.300, respectively). It was concluded that radiofrequency radiation exposure significantly increased the risk of breast cancer, especially in women aged ≥50 years and in individuals who used electric appliances, such as mobile phones and computers. In accordance with Preferred Reporting Items for Systematic Reviews and Meta-analysis, an evaluation protocol was prepared and registered with the PROSPERO database (registration no. CRD42018087283).

Evaluation of Short-Term Exposure to 2.4 GHz Radiofrequency Radiation Emitted from Wi-Fi Routers on the Antimicrobial Susceptibility of Pseudomonas aeruginosa and Staphylococcus aureus

Background

Overuse of antibiotics is a cause of bacterial resistance. It is known that electromagnetic waves emitted from electrical devices can cause changes in biological systems. This study aimed at evaluating the effects of short-term exposure to electromagnetic fields emitted from common Wi-Fi routers on changes in antibiotic sensitivity to opportunistic pathogenic bacteria.

Materials and Methods

Standard strains of bacteria were prepared in this study. Antibiotic susceptibility test, based on the Kirby-Bauer disk diffusion method, was carried out in Mueller-Hinton agar plates. Two different antibiotic susceptibility tests for Staphylococcus aureus and Pseudomonas aeruginosa were conducted after exposure to 2.4-GHz radiofrequency radiation. The control group was not exposed to radiation.

Results

Our findings revealed that by increasing the duration of exposure to electromagnetic waves at a frequency of 2.4 GHz, bacterial resistance increased against S. aureus and P. aeruginosa, especially after 24 hours (P<0.05).

Conclusion

The use of electromagnetic waves with a frequency of 2.4 GHz can be a suitable method for infection control and treatment.

Antibacterial Susceptibility Pattern of the Pseudomonas aeruginosa and Staphylococcus aureus after Exposure to Electromagnetic Waves Emitted from Mobile Phone Simulator

Background:

The increasing use of telecommunication devices such as Wi-Fi modems and mobile phones in the recent years can change the cellular structure of microorganisms so the generation of electromagnetic waves has led to concern in the community whenever be exposed to these fields and may have harmful effects on human health.

Material and Methods:

In this experimental study, standard strains of bacteria were prepared on Mueller-Hinton agar for bacterial growth to obtain 0.5 McFarland turbidity (1.5 × 10⁸ CFU) of bacteria. Antibiotic susceptibility test using the Kirby-Bauer disk diffusion method was done. For Staphylococcus aureus and Pseudomonas aeruginosa, antibiotics susceptibility test was conducted. The test group was exposed to electromagnetic waves emitted by mobile phone simulator with a frequency of 900 MHz and the control group were not exposed.

Results:

The results revealed that increasing duration of exposure to electromagnetic waves emitted by the mobile simulators with a frequency of 900 MHz especially after 24 h of exposure, can increase bacterial resistance in S. aureus, and P. aeruginosa.

Conclusion:

Several factors can cause bacterial resistance against antibiotics. One of these factors is the electromagnetic waves emitted from mobile simulator with a frequency of 900 MHz, which can increase the permeability of the cell wall of bacteria.

Global gene expression analysis of Escherichia coli K-12 DH5α after exposure to 2.4 GHz wireless fidelity radiation

This study investigated the non-thermal effects of Wi-Fi radiofrequency radiation of 2.4 GHz on global gene expression in Escherichia coli K-12 DH5α. High-throughput RNA-sequencing of 2.4 GHz exposed and non-exposed bacteria revealed that 101 genes were differentially expressed (DEGs) at P ≤ 0.05. The up-regulated genes were 52 while the down-regulated ones were 49. QRT-PCR analysis of pgaD, fliC, cheY, malP, malZ, motB, alsC, alsK, appB and appX confirmed the RNA-seq results. About 7% of DEGs are involved in cellular component organization, 6% in response to stress stimulus, 6% in biological regulation, 6% in localization, 5% in locomotion and 3% in cell adhesion. Database for annotation, visualization and integrated discovery (DAVID) functional clustering revealed that DEGs with high enrichment score included genes for localization of cell, locomotion, chemotaxis, response to external stimulus and cell adhesion. Kyoto encyclopedia of genes and genomes (KEGG) pathways analysis showed that the pathways for flagellar assembly, chemotaxis and two-component system were affected. Go enrichment analysis indicated that the up-regulated DEGs are involved in metabolic pathways, transposition, response to stimuli, motility, chemotaxis and cell adhesion. The down-regulated DEGs are associated with metabolic pathways and localization of ions and organic molecules. Therefore, the exposure of E. coli DH5α to Wi-Fi radiofrequency radiation for 5 hours influenced several bacterial cellular and metabolic processes.

Evaluation of Wi-Fi Radiation Effects on Antibiotic Susceptibility, Metabolic Activity and Biofilm Formation by Escherichia Coli 0157H7, Staphylococcus Aureus and Staphylococcus Epidermis

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, 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.