Introduction: Bacterial adhesion on medical devices can have serious consequences, somtimes leading to chronic infections if biofilm formation cannot be prevented. When bacteria colonies form in surgical sites, the bacteria contribute to prolonged inflammation, delay tissue regeneration, and jeopardize the natural healing process. The formation of biofilms is a significant health issue, as they cannot be prevented using conventional antimicrobial treatments. It has been reported in the literature that electrical stimulation (ES) may result in bacteria inhibition through molecular regulatory mechanisms. The current study explores the effect of low-level ES on Staphylococcus epidermidis (S.epidermis) and Escherichia coli (E.coli), and our results show a promising E.coli inhibition efficiency was achieved.
Methods: Petri dishes with Grade 5 cpTi rods as electrodes were fabricated with a separation distance of 3cm between electrodes. A total of 20mL of Tryptic Soy Agar was dispensed into each dish and bacteria species were grown up to the mid-log phase, before a bacterial lawn was created. Then, 30 minutes of ES was delivered at varying voltages (1V, 300mV, and 100mV) and frequencies (3MHz, 1MHz, 0.75MHz, and 0.5MHz) and samples were then incubated at 37C for 24 hours. The zone of inhibition (ZOI) around the electrodes after incubation was measured using ImageJ.
Results: All ES parameters showed various levels of inhibition against E.coli. Based on the data collected, 1V at 1MHz showed the largest ZOI with a statistical difference compared to 100mV at 1MHz and 1V at 0.5MHz. There was no inhibition of growth at any ES parameter when tested against S.epidermis.
Conclusions: The use of low-level ES against bacteria growth has major clinical applications that can help reduce post-operative infection risk and lower the risk of antibiotic resistance. The results indicate a need for further research to understand the influence of ES parameters on various bacteria. Future studies will include ES against other common bacterial species associated with infections.
