Catheter-Based Medical Device Biofilm Ablation Using Histotripsy: A Parameter Study.

Area of Science:

• Biomedical Engineering
• Infectious Diseases
• Medical Devices

Background:

• Catheter-associated biofilms are a primary cause of hospital-acquired infections.
• Histotripsy is a non-invasive, non-thermal focused ultrasound therapy.
• Existing histotripsy methods for biofilm removal are time-consuming.

Purpose of the Study:

• To investigate methods for increasing the speed and efficiency of histotripsy-based biofilm ablation from medical catheters.
• To explore the bactericidal effects of optimized histotripsy parameters on planktonic bacteria.

Main Methods:

• Cultured Pseudomonas aeruginosa (PA14) biofilms in vitro Tygon catheter mimics.
• Treated biofilms with histotripsy using a 1 MHz transducer, varying pulsing rates and scanning methods.
• Applied optimized parameters to assess bactericidal effects on planktonic PA14.

Main Results:

• Achieved near-complete biofilm removal at treatment speeds up to 1 cm/s.
• Demonstrated a 4.241 log reduction in planktonic bacteria at 2.4 cm/min.
• Observed a 500-fold increase in biofilm removal speed and a 6.2-fold increase in bacterial killing speed compared to previous methods.

Conclusions:

• Optimized histotripsy parameters enable significantly faster biofilm removal and bacterial killing.
• Histotripsy shows potential for treating catheter-associated biofilms and planktonic bacteria within clinically relevant timeframes.