Bacterial growth rates are influenced by cellular characteristics of individual species when immersed in electromagnetic fields.

Microbiological research · 2015 · Mixed · Low evidence

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MixedLow evidencePaper 4791

Study snapshot

PublicationMicrobiological research · 2015

Study typeother

Reported directionMixed

Evidence ratingLow

Abstract

Previous studies have shown that exposure to extremely low-frequency electromagnetic fields (ELF-EMFs) have negative effects on the rate of growth of bacteria. In the present study, two Gram-positive and two Gram-negative species were exposed to six magnetic field conditions in broth cultures. Three variations of the 'Thomas' pulsed frequency-modulated pattern; a strong-static "puck" magnet upwards of 5000G in intensity; a pair of these magnets rotating opposite one another at ∼30rpm; and finally a strong dynamic magnetic field generator termed the 'Resonator' with an average intensity of 250μT were used. Growth rate was discerned by optical density (OD) measurements every hour at 600nm. ELF-EMF conditions significantly affected the rates of growth of the bacterial cultures, while the two static magnetic field conditions were not statistically significant. Most interestingly, the 'Resonator' dynamic magnetic field increased the rates of growth of three species (Staphylococcus epidermidis, Staphylococcus aureus, and Escherichia coli), while slowing the growth of one (Serratia marcescens). We suggest that these effects are due to individual biophysical characteristics of the bacterial species.

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AI evidence extraction

Structured fields below were generated from the paper’s abstract and metadata to make the evidence easier to inspect. Automated extraction may be incomplete or incorrect; verify important details against the original paper.

Study typeother

Effect directionmixed

PopulationBroth cultures of two Gram-positive and two Gram-negative bacterial species (Staphylococcus epidermidis, Staphylococcus aureus, Escherichia coli, Serratia marcescens)

Sample sizeNot supplied

ExposureELF

Evidence strengthLowConfidence: 74% · Peer reviewed: yes

Main findings

Across six magnetic field conditions, ELF-EMF conditions significantly affected bacterial growth rates, while two static magnetic field conditions were not statistically significant. A dynamic magnetic field generator ('Resonator', average intensity 250 μT) increased growth rates of Staphylococcus epidermidis, Staphylococcus aureus, and Escherichia coli, but slowed growth of Serratia marcescens.

Outcomes measured

Bacterial growth rate (optical density at 600 nm measured hourly)

Limitations

Sample size and replication details not provided in the abstract
Exposure frequencies for the pulsed frequency-modulated patterns not specified
Exposure duration not specified beyond hourly OD measurements
Study is in vitro (broth cultures), limiting direct applicability to human health

View raw extracted JSON

{
  "study_type": "other",
  "exposure": {
    "band": "ELF",
    "source": "other",
    "frequency_mhz": null,
    "sar_wkg": null,
    "duration": null
  },
  "population": "Broth cultures of two Gram-positive and two Gram-negative bacterial species (Staphylococcus epidermidis, Staphylococcus aureus, Escherichia coli, Serratia marcescens)",
  "sample_size": null,
  "outcomes": [
    "Bacterial growth rate (optical density at 600 nm measured hourly)"
  ],
  "main_findings": "Across six magnetic field conditions, ELF-EMF conditions significantly affected bacterial growth rates, while two static magnetic field conditions were not statistically significant. A dynamic magnetic field generator ('Resonator', average intensity 250 μT) increased growth rates of Staphylococcus epidermidis, Staphylococcus aureus, and Escherichia coli, but slowed growth of Serratia marcescens.",
  "effect_direction": "mixed",
  "limitations": [
    "Sample size and replication details not provided in the abstract",
    "Exposure frequencies for the pulsed frequency-modulated patterns not specified",
    "Exposure duration not specified beyond hourly OD measurements",
    "Study is in vitro (broth cultures), limiting direct applicability to human health"
  ],
  "evidence_strength": "low",
  "confidence": 0.74,
  "peer_reviewed_likely": "yes",
  "keywords": [
    "extremely low-frequency electromagnetic fields",
    "ELF-EMF",
    "magnetic field",
    "static magnetic field",
    "dynamic magnetic field",
    "Resonator",
    "Thomas pulsed pattern",
    "bacterial growth",
    "optical density",
    "Staphylococcus epidermidis",
    "Staphylococcus aureus",
    "Escherichia coli",
    "Serratia marcescens"
  ],
  "suggested_hubs": []
}

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AI-extracted fields are generated from the abstract and metadata and may be incomplete or incorrect. This material is for informational purposes and is not medical advice.

Identifiers and source

DOI: 10.1016/j.micres.2014.12.008
PubMed: 25721476

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