Galvanic current dosage and bacterial concentration are determinants of the bactericidal effect of percutaneous needle electrolysis: an in vitro study

Abstract

Percutaneous needle electrolysis (PNE) is a physiotherapy technique that has been shown to be effective in different pathologies such as tendinopathies or mammary fistula. For many years, theoretical bactericidal and germicidal effects have been attributed to this type of galvanic currents, partly explained by the changes in pH that it generates. However, these effects have not yet been demonstrated. The aim of this study was to evaluate the bactericidal effect and the changes in pH caused by PNE. S. aureus were prepared in two different solutions (TSB and saline solution) and in different concentrations (from 9 to 6 Log10 CFU/mL). Bacteria were treated with three experimental PNE doses to assess bacterial death levels and the changes caused to the pH of the medium. The viable cell count showed that all experimental PNE doses had a bactericidal effect against a high concentration (9 Log10 CFU/mL) of S. aureus in saline solution (p < 0.001). Furthermore, we found that when the concentration of bacteria decreased, a lower dose of galvanic current generated the same effect as a higher dose. Changes in pH were registered only in experiments performed with saline solution. PNE had a bactericidal effect against S. aureus and the level of this effect was mainly modulated by the solution, the bacterial concentration and the dose. Changes affecting pH were modulated by the type of solution and there was no relationship between this and bacterial death.

In vitro bacteriological effect of tri-beveled needle electrolysis against Staphylococcus aureus

“…Based on the results obtained, the needle gauge seems not have a lineal relationship with the level of bacterial death. Our results with needles of the smallest gauge were similar to previous in vitro studies that found good results using acupuncture needles (0.30 mm × 30 mm) with current doses of 0.125 C 14 . This equivalence between studies strengthens our affirmation.…”

“…Furthermore, since we found that the bactericidal effect does not depend on the needle gauge, we could use NE in pathologies of multiple locations and different sizes, from mammary fistulas which can have a different diameter and volume 16 , 17 , to hidradenitis suppurativa which are usually located in small areas of the armpits or inguinal fold 22 . In addition, since previous authors 14 have pointed out that it can have a needle dragging effect in percutaneous applications, these findings offer greater safety to this novel technique.…”

“…Nevertheless, it is possible that other bacteria concentrations may require a different optimal dose. Considering that we also identified in a previous study that dose interacts with bacterial concentration for determining the bactericidal effect 14 , we decided to select a high concentration, which would be what we could find in a major infection. In our opinion, these two findings open up a wide range of possibilities for future studies.…”

“…This application of galvanic current by needles has been called needle electrolysis (NE), which is considered to be a minimally invasive approach that generates different alkaline molecules, capable of generating a non-thermal electrochemical ablation by cathodic flow directly into the affected tissue 12 . Recently, a bactericidal effect has been demonstrated in vitro with this type of needle used in acupuncture 14 .…”