Inactivation of spores by electric arcs

Pillet, Flavien; Marjanović, Igor; Reberšek, Matej; Miklavčič, Damijan; Rols, Marie‐Pierre; Kotnik, Tadej

doi:10.1186/s12866-016-0764-x

Cited by 5 publications

(3 citation statements)

References 21 publications

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“…And second, spores, produced by many G+ bacterial strains, are much more resistant to electroporation, and physical stress in general, than the bacteria that produce them (Setlow, 2010;Pillet et al, 2016). Thus, the spores surviving the treatment and then germinating within the time window in which the inhibition and inactivation are studied can significantly distort any G+ vs. G− comparison of treatments involving electroporation.…”

Section: Discussionmentioning

confidence: 99%

Antibiotic’s target site affects the potentiation of Lactiplantibacillus plantarum inhibition and inactivation by electroporation

Lovšin,

Kotnik,

Klančnik

2024

Front. Microbiol.

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IntroductionAntibiotic resistance represents a growing global threat, and thus the motivation to develop novel and combined methods of bacterial inactivation is increasing. Electroporation is a technique in which electric pulses of sufficient strength are applied to permeabilize cells, including bacteria. Combining antibacterials with electroporation is a promising strategy to potentiate their bactericidal and bacteriostatic effectiveness. This approach has already proved useful for increasing bacterial inactivation, yet most studies so far have mainly focused on the maximal achievable effects, and less on the underlying mechanisms. We recently demonstrated that in the Gram-negative (G–) bacterium Escherichia coli, electroporation potentiates antibacterials targeting the peptidoglycan wall more than those with intracellular targets. However, in Gram-positive (G+) bacteria, the wall is directly accessible from the outside, and thus the dependence of potentiation on the antibacterial’s target may be rather different. Here, we compare the inactivation and growth inhibition of the G+ bacterium Lactiplantibacillus plantarum for two antibiotics with different modes of action: ampicillin (inhibits cell-wall synthesis) and tetracycline (inhibits intracellular protein synthesis).MethodsWe used antibiotic concentrations ranging from 0 to 30 × MIC (minimum inhibitory concentration that we predetermined for each antibiotic), a single 1-ms electric pulse with an amplitude from 0 to 20 kV/cm, and post-pulse pre-dilution incubation of 24 h or 1 h.ResultsElectroporation increased the inhibition and inactivation efficiency of both antibiotics, but this was more pronounced for tetracycline, with statistical significance mostly limited to 24-h incubation. In general, both inhibition and inactivation grew stronger with increasing antibiotic concentration and electric field amplitude.DiscussionOur results indicate that electroporation potentiates inactivation of G+ bacteria to a larger extent for antibiotics that inhibit intracellular processes and require transport into the cytoplasm, and to a smaller extent for antibiotics that inhibit cell-wall synthesis. This is the inverse of the relation observed in G– bacteria, and can be explained by the difference in the envelope structure: in G– bacteria the outer membrane must be breached for wall-inhibiting antibiotics to access their target, whereas in G+ bacteria the wall is inherently accessible from the outside and permeabilization does not affect this access.

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Section: Discussionmentioning

confidence: 99%

Antibiotic’s target site affects the potentiation of Lactiplantibacillus plantarum inhibition and inactivation by electroporation

Lovšin,

Kotnik,

Klančnik

2024

Front. Microbiol.

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“…16 Recent research into the inactivation of Bacillus and Clostridium endospores focused on high temperatures combined with high pressure (eg, autoclave), [17][18][19] vaporized hydrogen peroxide, 20 and electric arcs. 21 Because we investigated only one endospore-forming species, additional species should be studied. Further studies into the inactivation of endospore-forming bacteria through heat stabilization treatment should also consider longer durations of treatment, higher temperatures, and/or combined chemical inactivation.…”

Section: Discussionmentioning

confidence: 99%

Rapid Inactivation of Non-Endospore-Forming Bacterial Pathogens by Heat Stabilization is Compatible with Downstream Next-Generation Sequencing

Schroeder

Loparev

2019

Appl Biosaf.

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Introduction: Heat stabilization treatment preserves the in vivo state of biological samples by rapidly inactivating enzymes that cause degradation of proteins and nucleic acids. Historically, proteomics studies used this technique as an alternative to chemical fixation. More recently, microbiologists discovered that heat stabilization treatment rapidly inactivates pathogens present in tissue samples and preserves deoxyribonucleic acid (DNA) in the tissue. However, these recent studies did not investigate the inactivation of high-density bacterial suspensions and the quality of bacterial DNA. Methods and Results: High-density suspensions of Escherichia coli (>109 cfu/mL) were completely inactivated by heat stabilization treatment using the Denator Stabilizor T1 instrument at 72°C and 95°C for 45 seconds. Using the heat stabilization instrument, a panel of 30 species, 20 Gram-negative and 10 non-endospore-forming Gram-positive species, were fully inactivated by treatment (95°C for 45 seconds). DNA was isolated from bacterial suspensions of Gram-negative bacteria, including E. albertii, E. coli, Shigella dysenteriae, and S. flexneri, following inactivation via heat stabilization treatment and without treatment. DNA isolated following heat stabilization treatment was fully compatible with all downstream molecular applications tested, including next-generation sequencing, pulsed-field gel electrophoresis, multiplex polymerase chain reaction (PCR), and real-time PCR. Conclusions and Discussion: Heat stabilization treatment of Gram-negative and non-endospore-forming Gram-positive pathogens completely inactivates high-density bacterial suspensions. This treatment is compatible with downstream DNA molecular assays, including next-generation sequencing, pulsed-field gel electrophoresis, and PCR. Inactivation by heat stabilization is a rapid process that may increase safety by decreasing risks for laboratory-associated infections and risks associated with transportation of infectious materials.

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“…Further, many researchers are investigating the efficacy of various inactivating agents against spores of Bacillus anthracis and its surrogates since the ‘anthrax letter’ attacks in 2001 (Nicholson & Galeano 2003; CDC 2006; Pillet et al . 2016 a , b ; Raguse et al . 2016).…”

Section: Introductionmentioning

confidence: 99%

Purification procedure sensitizesBacillusendospores to free radicals from UVA radiation and photocatalysis

Krishna

Zhao

Koopman

et al. 2017

International Journal of Astrobiology

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Many researchers are investigating the extreme resilience of bacterial endospores against chemical and physical inactivating agents. The presence of vegetative cells in spore suspensions can result in overly optimistic assessment of inactivating agents; therefore, various spore purification methods have been applied to separate spores from vegetative cells prior to testing. The present study was undertaken to evaluate the effect of two widely used spore purification methodologies on spore integrity and susceptibility to ultraviolet-A (UVA) radiation and free radicals generated from photocatalysts. Bacillus subtilis and Bacillus cereus spores were purified by procedures that involved heat shock alone or chemical washes, lysozyme treatment and heat shock (CLH). The purified spores were exposed to UVA radiation or free radicals generated by photocatalyst and susceptibility were evaluated in terms of survival ratio. The effect of purification procedure on the spore morphology was investigated with electron microscopy. The CLH purification process significantly damages spore coats and increases the susceptibility of Bacillus spores to UVA radiation and photocatalytic inactivation. It is therefore likely that the survival of CLH treated spores in extra-terrestrial environments would be less than that of the same spores purified by a less aggressive procedure.

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Inactivation of spores by electric arcs

Cited by 5 publications

References 21 publications

Antibiotic’s target site affects the potentiation of Lactiplantibacillus plantarum inhibition and inactivation by electroporation

Antibiotic’s target site affects the potentiation of Lactiplantibacillus plantarum inhibition and inactivation by electroporation

Rapid Inactivation of Non-Endospore-Forming Bacterial Pathogens by Heat Stabilization is Compatible with Downstream Next-Generation Sequencing

Purification procedure sensitizesBacillusendospores to free radicals from UVA radiation and photocatalysis

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