Study type: Medical/biological study (experimental study)

Evaluations of the Effects of Extremely Low-Frequency Electromagnetic Fields on Growth and Antibiotic Susceptibility of Escherichia coli and Pseudomonas aeruginosa. med./bio.

Published in: Int J Microbiol 2012: 587293

Aim of study (acc. to author)

To investigate the effects of an exposure to extremely low-frequency magnetic fields on the growth rate and antibiotic sensitivity of the bacteria strains Escherichia coli and Pseudomonas aeruginosa.

Background/further details

The growth rates were determined for following groups: 1.) control group, 2.) expoure group, 3.) kanamycin, 4.) kanamycin + exposure, and 5.) amikacin + exposure.
The antibiotic susceptibility was determined by the minimal inhibitory concentration (the dilution value at which no visible growth occurred in the bacteria) of the two bacteria strains in presence and absence of an extremely low-frequency magnetic field. Following antibiotics were tested: kanamycin, amikacin, ampicillin, ceftazidime, levofloxacin, cefazolin, ceftriaxone, and moxalactam.

Endpoint

Exposure

Exposure Parameters
Exposure 1: 50 Hz
Exposure duration: continuous for up to 24 h

General information

Following groups were investigated: 1.) control group 2.) expoure group 3.) kanamycin 4.) kanamycin + exposure 5.) amikacin + exposure

Exposure 1

Main characteristics
Frequency 50 Hz
Type
Waveform
Exposure duration continuous for up to 24 h
Exposure setup
Exposure source
Setup pair of Helmholtz coils with a mean radius of 13 ± 0.5 cm; each coil consisted of 800 turns of 2 mm² wire; coils spaced vertically 13.5 ± 0.5 cm apart; field uniformity better than 1% in the exposure area; four Falcon multiwell plates with 96 wells or twelve 20 ml glas tubes exposed simultaneously; exposure system placed inside an incubator with constant temperature of 37 ± 0.3 °C
Sham exposure A sham exposure was conducted.
Parameters
Measurand Value Type Method Mass Remarks
magnetic flux density 2 mT - measured - -

Exposed system:

Methods Endpoint/measurement parameters/methodology

Investigated system:
Time of investigation:
  • during exposure
  • after exposure

Main outcome of study (acc. to author)

No remarkable differences were found in the antibiotic susceptibility and on the growth rates of both bacteria comparing the exposed group (group 2) with the control group (group 1).
However, exposure to an extremely low-frequency magnetic field showed a significant effect on the growth rate of both strains when incubated in the presence of subinhibitory concentrations of kanamycin (1 µg/ml, group 4) and amikacin (O.5 µg/ml, group 5). In particular, at 4, 6, and 8 h exposure the number of cells was significantly decreased in exposed bacteria compared with the control (group 3). Additionally, at 24 h exposure, the percentage of cells increased in treated groups with respect to the control group suggesting a progressive adaptive response.

Study character:

Study funded by

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