Inactivation of bacteria using different Histotripsy regimes: Toward the treatment of abscesses

Abstract

Infected abscesses are defined as localized collections of infected purulent material delineated by a capsule composed of granulation and connective tissue. They can affect any part of the body. Current treatment typically involves antibiotics with either long-term catheter drainage or incision and washout. Given the ubiquitous nature of bacteria and the serious threat of multi-drug resistant strains, abscesses have become a persistent global healthcare problem. Using histotripsy, a potential new noninvasive treatment modality, we have evaluated bacterial inactivation of Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) microbes. We have determined the peak negative pressure threshold for inactivation of E. coli in solution for cavitation histotripsy (low cycles, high pulse repetition rate) and boiling histotripsy (high cycles, high pulse repetition rate) for different treatment times. The effect of transducer frequency on bacterial inactivation has also been evaluated. The optimal regimen was used to evaluate the S. aureus inactivation. Bacterial inactivation has also been evaluated in an abscess phantom model. Custom transducers have been developed and evaluated in an animal model for abscesses. [Work supported in part by NIH NIBIB #R01EB019365 and NIAID #R01AR080120.]