Effect of alternating and direct currents on <i>Pseudomonas aeruginosa</i> growth <i>in vitro</i>

Abstract

Eradication of pathogenic bacteria from important part of our life such as dental tools, foods and wounds is necessary. Based on the effect of natural selection, these bacteria become resistant to antibiotics. In some cases such as the section where burnt are treated in the hospital, we observe high rate of mortality as well as high numbers of resistant bacteria. In order to solve these problems, electrical stimulation (ES) is proposed. This has being shown to be an effective method. One of the reasons why it works could be due to the bacteria static property of electrical stimulation. So, more studies must be done so as to reach optimum voltage and currents. The test media were Muller-Hinton agar and eosin methylene blue (EMB) agar. In this research Pseudomonas aeruginosa which was isolated from patients wounds was examined with levels of alternating and direct current (AC and DC) electrical stimulation (1.5V, 3.5V, 5.5V and 10V) to see if these currents could inhibit P. aeruginosa growth in vitro. The experiment was performed in two forms: The first was carried out immediately while the second was carried out 19 h after being cultured. Different patterns of zone of inhibition were observed in the two forms of our research. AC current had low inhibitive effect on P. aeruginosas growth. Anode and cathode showed different zone of inhibition, in each of the forms and media. The maximum inhibition zone (22 mm) was observed around cathode in 3.5 V direct current which was immediately used in the media. Direct current significantly inhibits growth of P. aeruginosa. Based on other studies on different bacterial species, ES can be applied to sterilization and controlling of superficial infections like in burnt patients.

Key words: Electrical stimulation, Pseudomonas aeruginosa, wound healing.