Apparent growth paradox of Staphylococcus epidermidis in response to extremely low frequency electromagnetic radiation exposure

Abstract

Staphylococcus epidermidis is a normal part of the human microbiome; however, it is an opportunistic pathogen and can cause infections when the delicate balance of this microbiome is disrupted. Furthermore, infections caused by this bacterium can be hard to treat as a result of antibiotic resistance and biofilm production. This experiment aimed to determine whether electromagnetic field radiation (ELF-EMF) could be a deterrent of bacterial growth, as an alternative treatment to antibiotics. A non-pathogenic strain of S. epidermidis was used for experimentation, which took place in a school laboratory setting. The experimental group was exposed to ELF-EMF, while the control group did not receive the ELF-EMF treatment. The number of bacterial colonies, represented as colony forming units (CFUs) and area of random colonies were calculated to determine the effect of this treatment. There was no dramatic difference of colony formation on days 0, 1, and 2 of the four day period of ELF-EMF exposure. However, colony formation for days 3 and 4 showed a significant difference between the control and the experimental groups, as the experimental group had a significantly higher CFU count than the control. The average CFU count for day 3 in the control group was 420.6 and 1,097.4 for the experimental group (p<0.0001, t=12.9803). On the final day of the experimentation (Day 4) the average CFU count for the control group was 424.6 and 896.4 for the experimental group (p<0.0001, t=5.8926). The area for five randomly chosen colonies from each petri dish was calculated on the fourth day of experimentation. The area for the experimental group was significantly lower than that control (p<0.0001, with t=6.8659). The average area for the control group was 1.3249 mm2 and a lower average of 0.6375mm2 for the experimental group. These results demonstrate that the ELF-EMF treatment had an inhibitory effect on the area growth of S. epidermidis, but not on the colony-forming ability of S. epidermidis. This suggests that ELF-EMF influences the means by which the bacterium S. epidermidis grows.