REDUCING BIOFILM ASSOCIATED INFECTIONS BY SURFACE ACOUSTIC WAVES

During the past decade there has been a notable increase in attempts to develop new techniques for preventing and treating biofilm infections. Since Ultrasound waves are hardly absorbed by tissues and ultrasonic treatment is a non-invasive and painless procedure of transmitting energy, it has been extensively studied for the delivery of therapeutic agents. On the present study we used a new ultrasonic device, UroShield (Nanovibronix LTD.), which generates low-energy Surface Acoustic Waves (SAW). The device is attached to a urinary catheter and produces SAW along the catheter. Our results show that SAW can reduce (by 98%) the ability of P. aeruginosa to form biofilms on catheters. We also screened, the ability of SAW to enhance the efficacy of antibiotics. A reduction of two log’s in biofilm biomass was achieved when biofilms were treated with combined SAW and gentamicin compared to antibiotic treatment alone (similar results were obtained with Staphylococcus epidermidis and Escherichia coli). Transcriptome analysis results show that SAW treatment specifically alters gene expression of P. aeruginosa cells in biofilms. For example, genes related to the Type III secretion system and to two antibiotic resistance modules were down regulated following exposure to SAW treatment. In addition we identified a possible regulator, sawR that is highly expressed under SAW and influences biofilm formation, antibiotic resistance and virulence. These findings, highlight the potential of using SAW to reduce as well as treat urinary catheter infections and demonstrates for the first time a specific bacterial response to an acoustic treatment.