Medical/biological study (experimental study)

Effect of extremely low frequency electromagnetic fields on growth rate and morphology of bacteria med./bio.

By: Inhan-Garip A, Aksu B, Akan Z, Akakin D, Ozaydin AN, San T

Published in: Int J Radiat Biol 2011; 87 (12): 1155-1161

Aim of study (acc. to author)

To study the effect of extremely low frequency electromagnetic fields on the growth rate of gram-positive and gram-negative bacteria and to determine any morphological changes that might have been caused by exposure.

Endpoint

cell viability/cell division/proliferation: growth rate of bacteria
morphol./histopathol. changes: morphological changes

Exposure

Exposure	Parameters
Exposure 1: 50 Hz Exposure duration: continuous for up to 6 h	magnetic flux density: 0.5 mT (+/- 0.05 mT)

Exposure 1

Main characteristics

Frequency	50 Hz
Type	magnetic field
Exposure duration	continuous for up to 6 h

Exposure setup

Exposure source	Helmholtz coils
Setup	Helmholtz coils with an inner diameter of 20 cm and 400 turns of copper wire positioned parallel to the ground; 15 ml falcon tube containing culture medium of 1 cm height centered in the vertical axis of the coil system; exposure system placed in an incubator
Sham exposure	A sham exposure was conducted.

Parameters

Measurand	Value	Type	Method	Mass	Remarks
magnetic flux density	0.5 mT	-	measured	-	+/- 0.05 mT

Exposed system:

bacterium
gram-positive bacteria: Staphylococcus aureus, Staphylococcus epidermidis, Enterococcus faecalis; gram-negative bacteria: Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa

Methods Endpoint/measurement parameters/methodology

cell viability/cell division/proliferation: growth rate of bacteria (optical density and number of colony forming units)
morphol./histopathol. changes: morphological changes (uranyl acetate and lead citrate staining; transmission electron microscopy)

Investigated system:

Time of investigation:

during exposure
after exposure

Main outcome of study (acc. to author)

A decrease in growth rate was found for all bacterial strains during extremely low frequency electromagnetic field exposure compared with control samples. The decrease in growth rate persisted following exposure. Significant ultrastructural changes were observed in all exposed bacterial strains (e.g. disintegration of the cell wall, retraction of the cytoplasmic membrane from the cell wall, cell wall enlargement, cytoplasmic changes).
The data showed that extremely low frequency electromagnetic fields induce a decrease in growth rate and morphological changes for both gram-negative and gram-positive bacteria.

Study character:

medical/biological study
experimental study
full/main study

Study funded by

Marmara University Research Fund, Istanbul, Turkey

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