Method

Using a 12-well culture plate designed for the application of electrical fields, strains of S. epidermidis were incubated at each well for 24 hours at 37ºC. After incubation, supernatant culture medium was removed, and each well was filled with 3ml of normal saline. Six different models were compared: a) control, b) low-pressure pulse lavage, c) high-pressure pulse lavage, d) pulsed electrical fields, e) low-pressure pulse lavage in combination with pulsed electrical fields, and f) high-pressure pulse lavage in combination with pulsed electrical fields. In all cases, exposure time was set to 25 seconds. In the electrical field models, 50 pulses were applied.

After exposure, each bottom electrode was scraped carefully to release adhered bacteria. Subsequently, different dilutions of biofilm removed were spread onto Müller Hinton agar plates and incubated for 24h at 37 ºC, and colony-forming units (CFU) per milliliters were counted. Bacterial counts were then compared to the control model.