(448h) Biofilm Mitigation Via Magnetic Hyperthermia

Authors: 
O'Toole, A., University of Iowa
Nuxoll, E., University of Iowa



Bacterial biofilm infection is a common (~ 2 to 4%) complication for recipients of surgically implanted medical devices.  Due to the tremendous increase in antibiotic resistance when these bacteria enter the biofilm phenotype, present treatment requires explantation and replacement of the device, often with multiple surgeries and always with much longer patient recovery time.  The specific objective of this study is to determine the feasibility of using heat to deactivate these biofilms in situ.  While extreme heat is routinely used to sterilize (e.g. autoclaves), such temperatures have a severe cost within the body.  Despite extensive studies on thermal deactivation of bacteria in the planktonic phenotype over a wide range of temperatures (e.g., pasteurization protocols), surprisingly little is known about the thermal deactivation of biofilms except under extreme (>150 ˚C) conditions.  Here, we report the deactivation of Psuedomonas aeruginosa biofilms cultured at 37°C, 5% CO2 for 24 hours in a drip-flow reactor and subjected to heat shocks on the range of 50°C to 80°C for durations of 1 to 30 minutes.  Heat shocks were delivered by immersion in thermostatted media for the prescribed time and the resulting concentration of colony forming units (CFU/mL) were quantified using direct enumeration.  Up to 9 orders of magnitude reduction in CFU concentration was observed, indicating that thermal deactivation is a reasonable approach to biofilm mitigation.  By integrating this approach with a magnetic nanoparticle implant coating, we aim to treat implant infections in situ without explantation or device replacement.