Revealing detrimental effects of various DC electrical energy conditions on different multidrug resistant bacteria: a comprehensive study

TL;DR

This study shows that direct current electricity can effectively reduce multidrug-resistant bacteria by damaging their cells and decreasing antibiotic resistance.

Contribution

The study demonstrates the dose-dependent effectiveness of DC energy in reducing MDR bacteria and impairing their antibiotic resistance.

Findings

Exposure to 140 J of DC energy reduced bacterial counts by over 78% in Gram-negative bacteria and 47–73% in Gram-positive bacteria.

DC treatment impaired antibiotic resistance of the tested strains by more than 64.2%.

Electric energy caused cell wall deterioration and loss of membrane integrity, as indicated by protein and enzyme activity changes.

Abstract

The arbitrary discharge of contaminated wastes, especially that encompass multidrug resistant microbes (MDR), would broaden the circle of epidemic diseases such as COVID-19, which in turn deteriorate definitely the whole socioeconomics. Therefore, the employment of electrical stimulation techniques such as direct current (DC) with low energy considers being effective tool to impede spontaneous changes in microbial genetic makeup, which increases the prevalence of MDR phenomenon. Herein, the influence of different electric energies generated by DC electric field, volts and time on MDR-bacteria that are categorized among the highly ranked nosocomial pathogens, was scrutinized. Wherein, Pseudomonas aeruginosa, Escherichia coli, Staphylococcus aureus and Enterococcus faecalis were examined as paradigms of Gram-negative and Gram-positive pathogens. The results declared the significant superior antagonizing potency of electric energy in a dose-dependent modality rather than the applied volts or exposure time. Notably, the exposure of bacterial cultures to140 J inhibited the bacterial count by > 78% and the range of 47–73% for Gram-negative and Gram-positive, respectively. While the suppression in their metabolic activity assessed by > 75% and 41–68%, respectively; reflecting the capability of electrical energy to induce viable but non-culturable (VBNC) state. Similarly, the results of total protein, extracellular protein content and lactate dehydrogenase activity emphasized the cell wall deterioration and losing of cell membrane integrity. Additionally, the elevating in ROS upon DC-exposure participated in DNA fragmentation and plasmid decomposability by the range of 33–60%. Further, SEM micrographs depicted drastic morphological deformations after electrical treatment. Strikingly, DC-treatment impaired antibiotic resistance of the examined strains against several antibiotics by > 64.2%. Generally, our comparative detailed study revealed deleterious potentiality of different DC-protocols in defeating microbial pollution, which could be invested as efficient disinfectant alternative in various sectors such as milk sterilization and wastewater purification.

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