# Electric fields unlock a transient vulnerability window for vancomycin-based treatment of staphylococcal biofilms

## TL;DR

Electric fields temporarily weaken staphylococcal biofilms, making them more vulnerable to vancomycin treatment.

## Contribution

A novel bioelectric strategy using electric fields to enhance antibiotic efficacy against mature biofilms.

## Key findings

- Electric fields create a transient vulnerability window in Staphylococcus aureus biofilms.
- Vancomycin treatment during this window leads to a 3-log10 reduction in culturable cells.
- Effectiveness diminishes after the vulnerability window closes.

## Abstract

Bacterial biofilms pose a significant challenge to antibiotic treatment. Conventional therapeutic interventions often fail to effectively eradicate mature biofilms due to the protective extracellular matrix and altered physiological states of the embedded bacteria. In this study, we show that low-intensity sinusoidal electric fields induce a time-limited window of vulnerability in mature Staphylococcus aureus biofilms, increasing their susceptibility to vancomycin. In particular, the simultaneous application of electric fields and vancomycin during a transient vulnerability window results in a potentiated effect, leading to an approximately 3-log10 reduction in culturable cell counts relative to untreated controls. Conversely, the effectiveness of the antibiotic is reduced when vancomycin is administered after the cessation of the time-limited vulnerability window associated to the electrical stimulation, indicating a time-dependent reversibility of the electrical effect on the biofilm. These results suggest that the electric fields can create a critical phase of increased susceptibility to antibiotics, establishing a bioelectric strategy for biofilm control and highlighting the importance of treatment timing.