Delivery of delmopinol by silicone substrata to reduce biofilm formation
Sikora, Alexander J.
MetadataShow full item record
Catheter-associated urinary tract infections (CAUTIs) are the most frequent hospital-associated infections worldwide with an occurrence rate of over 40%. Typically this infection results from a biofilm formation on the catheter, which cannot be removed by physiologic (e.g. cytokines, phagocytes) or gentle mechanical means. In this study, delmopinol, a surface-active agent that has been efficacious in ridding biofilms in the oral environment without intrinsic bactericidal properties, was investigated as a potential removal aid for biofilms on silicone urinary catheters. Polydimethyl siloxane (PDMS silicone) substrata were prepared both by air curing and UV-C light-curing techniques. Delmopinol (1 and 5% w/v) was loaded into these silicone samples and elution of the delmopinol from the silicone substrata was determined using infrared spectroscopy. Model biofilms of Moraxella catarrhalis were grown in the presence of these loaded silicones and a silicone control. Bacterial growth was determined using turbidity testing of broth cultures. Differences in model biofilms on the treated vs. untreated silicone specimens were determined using visual analysis, contact angle goniometry, viscosity, IR spectroscopy, and jet-impingement testing. It was determined that neither delmopinol in solution nor in PDMS substrata at the prepared concentrations killed the bacteria at the concentrations used. Testing displayed visual and surface chemistry differences in an alginate-model biofilm matrix substance on control silicone versus PDMS loaded with delmopinol. Most relevant to this study was a decrease in matrix viscosity and cell-to-cell binding with the delmopinol-loaded samples compared to the control. This study has developed a feasible model with which to evaluate biofilm reduction on silicone substrata. In the presence of delmopinol, model biofilms have a decreased viscosity and cell-to-cell confluence, indicating a biomechanical path to reduce infections caused by biofilm formation on silicone substrata, such as in catheter-associated urinary tract infections and ear-tubes plugged from draining infections.