Alteration of Membrane Permeability of Bacteria and Yeast by High Frequency Alternating Current (HFAC)
C Cassanelli, A Marchese, S Cagnacci, E.A Debbia*
Identifiers and Pagination:Year: 2008
First Page: 32
Last Page: 37
Publisher ID: TOMICROJ-2-32
Article History:Received Date: 14/3/2008
Revision Received Date: 30/3/2008
Acceptance Date: 4/4/2008
Electronic publication date: 15/4/2008
Collection year: 2008
open-access license: This is an open access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.5/), which permits unrestrictive use, distribution, and reproduction in any medium, provided the original work is properly cited.
Endox® Endodontic System (Endox) is used for endodontic treatment by a high frequency alternating current (HFAC). This device damaged the envelopes of spores and vegetative organisms. If the integrity of the envelope is compromised, the transit of compounds in the two directions is possible. This latter aspect was investigated here.
The instrument delivered a 60ms pulse at a frequency 300 kHz, and power 800 KV/m. DNA transfer was verified using Escherichia coli K-12 strain carrying a non conjugative plasmid pBP517 (gyrA+) as donor and a rifampicin and nalidixic acid resistant recipient. 0.2 ml of mixture of donor and recipient strains in saline was exposed to HFAC and plated on selective media. Uptake of antimicrobials and a delay in re-growth was assessed exposing the strains to HFAC.
Plasmid transfer was detected under different experimental conditions. From 9 to 27 recombinants were found. Representative recombinants cured from plasmid showed the original phenotype. HFAC promoted the uptake of ineffective antibiotics, and induces a 1 h of delay in re-growth on the strains.
Endox exhibited an effect on microrganisms which is reminiscent with that occuring in electroporation, but with a mode of action that saved materials and time.