Time evolution of electrical impedance spectra of Staphylococcus aureus and Escherichia coli bacteria

This research work reports the time evolution of the electrical properties of gram-positive and gram-negative bacteria in aqueous suspensions with methyl violet and Lugol; measurements of galvanostatic electrical impedance spectra were made in a frequency range of 10 Hz to 100 kHz. The magnitude of the impedance as a function of frequency for methicillin-resistant strains, Staphylococcus aureus (gram-positive), and Escherichia coli O157: H7 (gram-negative) in the presence of methyl violet and Lugol, showed that both strains exhibited a progressive decrease in the magnitude of the electrical impedance with an increasing bacterial population; however, the variation in the magnitude rate of the impedance over time is completely different between the gram-positive and gram-negative strains. The results suggest that the time evolution of the electrical impedance spectra can be used to differentiate Staphylococcus aureus from Escherichia coli bacteria.

Automated summary

This research work investigates the time evolution of electrical properties of gram-positive and gram-negative bacteria in the presence of methyl violet and Lugol. The results show that the impedance magnitude decreases with an increasing bacterial population for both strains, but the rate of impedance magnitude variation over time is different between gram-positive and gram-negative bacteria. These findings suggest that the time evolution of electrical impedance spectra can be used to differentiate Staphylococcus aureus from Escherichia coli bacteria.