Synergistic bacterial inactivation by combining antibiotics with nanosecond electric pulses

Vadlamani, Anand; Detwiler, David A.; Dhanabal, Agni; Garner, Allen L.

doi:10.1007/s00253-018-9215-y

Cited by 22 publications

(18 citation statements)

References 35 publications

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“…In the present study we show in vitro results for the efficacy of 600-ns PEF to inactivate Escherichia coli and Lactobacillus acidophilus. While the effects of nsPEF have been studied on E. coli (Chalise et al 2006;Perni et al 2007;Guionet et al 2014Guionet et al , 2015Novickij et al 2018) and other species such as Staphylococcus aureus (Chaturongakul and Kirawanich 2012; Vadlamani et al 2018;Novickij et al 2019), Salmonella typhimurium (Perni et al 2007) and Bacillus subtilis (Katsuki et al 2002); we chose to compare the effects of E. coli with L. acidophilus for two reasons. First, several studies have suggested that cell size and shape play a critical role in transmembrane potential charging and subsequent membrane pore formation (Kandušer and Miklavčič 2008;Khan and El-Hag 2011).…”

Section: Discussionmentioning

confidence: 99%

600-ns pulsed electric fields affect inactivation and antibiotic susceptibilities of Escherichia coli and Lactobacillus acidophilus

et al. 2020

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Cell suspensions of Escherichia coli and Lactobacillus acidophilus were exposed to 600-ns pulsed electric fields (nsPEFs) at varying amplitudes or High-23.5 kV cm −1 ) and pulse numbers (0 (sham), 1, 5, 10, 100 or 1000) at a 1 hertz (Hz) repetition rate. The induced temperature rise generated at these exposure parameters, hereafter termed thermal gradient, was measured and applied independently to cell suspensions in order to differentiate inactivation triggered by electric field (E-field) from heating. Treated cell suspensions were plated and cellular inactivation was quantified by colony counts after a 24-hour (h) incubation period. Additionally, cells from both exposure conditions were incubated with various antibiotic-soaked discs to determine if nsPEF exposure would induce changes in antibiotic susceptibility. Results indicate that, for both species, the total delivered energy (amplitude, pulse number and pulse duration) determined the magnitude of cell inactivation. Specifically, for 18.5 and 23.5 kV cm −1 exposures, L. acidophilus was more sensitive to the inactivation effects of nsPEF than E. coli, however, for the 13.5 kV cm −1 exposures E. coli was more sensitive, suggesting that L. acidophilus may need to meet an E-field threshold before significant inactivation can occur. Results also indicate that antibiotic susceptibility was enhanced by multiple nsPEF exposures, as observed by increased zones of growth inhibition. Moreover, for both species, a temperature increase of ≤ 20 °C (89% of exposures) was not sufficient to significantly alter cell inactivation, whereas none of the thermal equivalent exposures were sufficient to change antibiotic susceptibility categories.

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Section: Discussionmentioning

confidence: 99%

600-ns pulsed electric fields affect inactivation and antibiotic susceptibilities of Escherichia coli and Lactobacillus acidophilus

et al. 2020

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“…However, with constant load on the sample being processed, excessive electric voltage will generate excessive electric current, causing bubbles in the liquid food and abnormal breakdown. It is hoped to be combined with other methods that may synergistically inactivate microorganisms to achieve more sufficient pasteurization (Garner 2019 , Vadlamani et al 2018 ). Applying combined PEF-thermal treatments can induce membrane pore formation and damage, including lysis (El Zakhem et al 2006 ).…”

Section: Introductionmentioning

confidence: 99%

Synergistic effect of pulsed electric fields and temperature on the inactivation of microorganisms

et al. 2021

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Pulsed electric fields (PEF) as a new pasteurization technology played an important role in the process of inactivating microorganisms. At the same time, temperature could promote the process of electroporation, and achieve better inactivation effect. This article studied the inactivation effect of PEF on Saccharomyces cerevisiae, Escherichia coli, and Bacillus velezensis under different initial temperatures (room temperature-24 $$\mathrm{^\circ{\rm C} }$$ ∘ C , 30 $$\mathrm{^\circ{\rm C} }$$ ∘ C , 40 $$\mathrm{^\circ{\rm C} }$$ ∘ C , 50 $$\mathrm{^\circ{\rm C} }$$ ∘ C ). From the inactivation results, it found temperature could reduce the critical electric field intensity for microbial inactivation. After the irreversible electroporation of microorganisms occurred, the nucleic acid content and protein content in the suspension increased with the inactivation rate because the cell membrane integrity was destroyed. We had proved that the electric field and temperature could promote molecular transport through the finite element simulation. Under the same initial temperature and electrical parameters (electric field intensity, pulse width, pulse number), the lethal effect on different microorganisms was Saccharomyces cerevisiae > Escherichia coli > Bacillus velezensis.

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“…Future tests combining differentiating and non-differentiating media with nsPEFs can determine whether this synergistically increases differentiation, analogous to our past studies assessing the synergy of antimicrobial agents with nsPEFs [43]. Polymerase chain reaction (PCR) tests can analyse changes in mRNA and the transcriptome that could indicate whether nsPEFs induce differentiation.…”

Section: Discussionmentioning

confidence: 89%

Nanosecond pulsed electric field induced proliferation and differentiation of osteoblasts and myoblasts

Vadlamani

Nie

Detwiler

et al. 2019

J. R. Soc. Interface.

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Low-intensity electric fields can induce changes in cell differentiation and cytoskeletal stresses that facilitate manipulation of osteoblasts and mesenchymal stem cells; however, the application times (tens of minutes) are of the order of physiological mechanisms, which can complicate treatment consistency. Intense nanosecond pulsed electric fields (nsPEFs) can overcome these challenges by inducing similar stresses on shorter timescales while additionally inducing plasma membrane nanoporation, ion transport and intracellular structure manipulation. This paper shows that treating myoblasts and osteoblasts with five 300 ns PEFs with intensities from 1.5 to 25 kV cm −1 increased proliferation and differentiation. While nsPEFs above 5 kV cm −1 decreased myoblast population growth, 10 and 20 kV cm −1 trains increased myoblast population by approximately fivefold 48 h after exposure when all cell densities were set to the same level after exposure. Three trials of the PEF-treated osteoblasts showed that PEF trains between 2.5 and 10 kV cm −1 induced the greatest population growth compared to the control 48 h after treatment. Trains of nsPEFs between 1.5 and 5 kV cm −1 induced the most nodule formation in osteoblasts, indicating bone formation. These results demonstrate the potential utility for nsPEFs to rapidly modulate stem cells for proliferation and differentiation and motivate future experiments to optimize PEF parameters for in vivo applications.

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Synergistic bacterial inactivation by combining antibiotics with nanosecond electric pulses

Cited by 22 publications

References 35 publications

600-ns pulsed electric fields affect inactivation and antibiotic susceptibilities of Escherichia coli and Lactobacillus acidophilus

600-ns pulsed electric fields affect inactivation and antibiotic susceptibilities of Escherichia coli and Lactobacillus acidophilus

Synergistic effect of pulsed electric fields and temperature on the inactivation of microorganisms

Nanosecond pulsed electric field induced proliferation and differentiation of osteoblasts and myoblasts

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