A radio frequency electric current enhances antibiotic efficacy against bacterial biofilms.

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http://www.ncbi.nlm.nih.gov/pubmed/15561841A radio frequency electric current enhances antibiotic efficacy against bacterial biofilms.

Caubet R, Pedarros-Caubet F, Chu M, Freye E, de Belém Rodrigues M, Moreau JM, Ellison WJ.

Unité

Sécurité Microbiologique des Aliments, Institut des Sciences et Techniques des Aliments de Bordeaux, Université de Bordeaux 1, Talence, France. r.caubet@...Abstract

Bacterial

biofilms are notably resistant to antibiotic prophylaxis. The concentration of antibiotic necessary to significantly reduce the number

of bacteria in the biofilm matrix can be several hundred times the MIC for the same bacteria in a planktonic phase. It has been observed that the addition of a weak continuous direct electric current to the liquid surrounding the biofilm can dramatically increase the efficacy of the antibiotic. This phenomenon, known as the bioelectric effect, has only been partially elucidated, and it is not certain that the electrical parameters are optimal. We confirm here the bioelectric effect for Escherichia coli biofilms treated with gentamicin and with oxytetracycline, and we report a new bioelectric effect with a radio frequency alternating electric current (10 MHz) instead of the usual direct current. None of the proposed explanations (transport of ions within the biofilm, production of additional biocides by electrolysis, etc.) of the direct current bioelectric effect are applicable to the radio frequency bioelectric effect. We suggest that this new phenomenon may be due to a specific action of the radio frequency electromagnetic field upon the polar parts of the molecules forming the biofilm matrix.