Effect of nanosecond pulsed electric field on Escherichia coli in water: inactivation and impact on protein changes.

AIMS

This article shows the effect of nanosecond pulsed electric field (nsPEF) on Escherichia coli, which could imply a durable change in protein expressions and then impacted the phenotype of surviving bacteria that might lead to increase pathogenicity.

METHODS AND RESULTS

The effects of nsPEF on E. coli viability and membrane permeabilization were investigated. One log10 reduction in bacterial counts was achieved at field strength of 10(7) V m(-1) with a train of 500 successive pulses of 60 × 10(-9) s. Incubation of germs after treatment with propidium iodide showed that membrane permeabilization was reversible. Possible protein changes of surviving bacteria were checked to assess potential phenotypical changes using two-dimensional electrophoresis. In our study, after 40 generations, only UniProt #P39187 was up-regulated with P ≤ 0·05 compared with the control and corresponded to the uncharacterized protein YtfJ. Antibiograms were used to check whether or not the pattern of cultivable bacteria after nsPEF deliveries changed.

CONCLUSIONS

The results tend to show that nsPEFs are able to inactivate bacteria and have probably no serious impact in E. coli protein patterns.

SIGNIFICANCE AND IMPACT OF THE STUDY

The use of nsPEF is a safe promising new nonthermal method for bacterial inactivation in the food processing and environmental industry.