Microbial Growth Inhibition by Alternating Electric Fields

Weak electric currents generated using conductive electrodes have been shown to increase the efficacy of antibiotics against bacterial biofilms, a phenomenon termed “the bioelectric effect. ” The purposes of the present study were (i) to find out whether insulated electrodes that generate electric fields without “ohmic” electric currents, and thus are not associated with the formation of metal ions and free radicals, can inhibit the growth of planktonic bacteria and (ii) to define the parameters that are most effective against bacterial growth. The results obtained indicate that electric fields generated using insulated electrodes can inhibit the growth of planktonic Staphylococcus aureus and Pseudomonas aeruginosa and that the effect is amplitude and frequency dependent, with a maximum at 10 MHz. The combined effect of the electric field and chloramphen-icol was found to be additive. Several possible mechanisms underlying the observed effect, as well as its potential clinical uses, are discussed. The use of physical means as an aid for modern medicine in the continuous battle against pathogenic microorganisms holds new prospects that only recently have begun to be widely rec-ognized. Light sources of various types are being used for photodynamic therapy in dentistry and dermatology (10, 13