According to a report of the National Health and Safety Network, catheter associated urinary tract infection (CAUTI) is one of the most common healthcare-associated infections (HAIs), with a prevalence of 13 ? 15% in the United States. CAUTIs are also blamed for increased morbidity and mortality of affected patients with an estimated 13,000 deaths annually and an average increase in the length of hospitalization by 4 days. Unfortunately, CAUTIs are difficult to treat because the pathogens commonly attach to the catheter wall and form a biofilm, which is a multicellular structure of attached microbes embedded an extracellular matrix produced by these attached cells. Due to the protection of the biofilm matrix and slow growth of attached cells, biofilm cells are up to 1,000 times more resistant to antimicrobials than the planktonic cells of the same species. Thus, these biofilms are difficult to eliminate and blockage of the drainage tube can occur, leading to stone formation and urinary tract infections. Treatment of CAUTIs with high doses of antimicrobial agents can also adversely promote the development of multidrug resistant bacteria. To better prevent and control CAUTIs, this team proposes a novel catheter design that can both prevent microbial adhesion and remove established biofilms on demand. These antifouling properties are enabled by active surface topographies with beating of micron-scale pillars on the surface of inner catheter wall. The pillars are designed with well-defined dimensions and Fe3O4 nanoparticles on the tip. With an insulated copper wire coiled around the catheter tube, a magnetic field can be created to drive the beating of pillars with tunable frequency and force level (by controlling the electric current running through the copper wire and thus the strength of the electromagnetic field). Complementary studies are proposed to optimize the design of surface topography for the best antifouling activities. The effects of active topographies on detached biofilm cells will be investigated by characterizing the gene expression, synthesis of adenosine triphosphate (ATP), and antimicrobial susceptibility of detached cells vs. original biofilm cells. The best design will be used to engineer a prototype catheter, which will be further evaluated with pooled human urine for long-term biofilm prevention (more than 90% reduction for 14 days compared to pillar-free control) and on-demand removal of mature biofilms (more than 99%) of seven CAUTI causative agents including both bacteria and fungi. Biocompatibility of the prototype catheter will be evaluated using mouse fibroblast and uroepithelial cells.
Bacterial biofilms play important roles in nosocomial infections including catheter associated urinary tract infections. This project aims to engineer novel non-fouling catheters which can provide long-term prevention of microbial adhesion and on-demand removal of established biofilms. The results will have direct impacts on patient care and recovery. Thus, it has significance in infection control, which is critical to public health.
