(134a) Heat Transfer Effects on Staphylococcus epidermidis Biofilms: An in vitro Catheter Model

Bacterial biofilms are a leading cause of hospital-acquired infections. The development of biofilms on medical devices, such as hemodialysis catheters, can be understood as a consequence of adsorption, growth, and detachment; each effect is governed by self-assembly, fluid mechanics, and transport phenomena which are governed by fundamental chemical engineering principles. Here we show how the fundamental chemical engineering principles of fluid dynamics and heat transfer can be applied to prevent and/or remove bacterial biofilms in an in vitro, flow cell model of a dialysis catheter. Using Staphylococcus epidermidis, the most common bacterial species isolated from infected medical devices, we grow biofilms under physiologically relevant flow conditions and expose them to thermal degradation using a pre-warmed fluid that is injected into the model catheter. We establish that exposing biofilms to elevated temperatures changes the biofilm morphology and cell viability. Further, we discuss the mechanism by which this degradation occurs in light of the two parameters temperature elevation and exposure duration. Finally, we probe the resilient, adaptive nature of bacterial cells to investigate if they develop thermal resistance when exposed to the heat treatment. Understanding the response of these bacterial cells under thermal stress is a promising step toward the development of an in situ treatment/remediation method for biofilm growth in medical devices.