Todd Meyer, PhD, Melissa Kelsey, BS. Bacterin International, Inc.
The pronounced incidence of device-associated infections has numerous causes and many corresponding potential solutions. Among these solutions is the coating of externally communicating devices with antimicrobial agents, with the objective of slowing or stopping transfer of exogenous flora from the skin to the interior of a wound. After a surgical procedure, a wound drain is frequently placed within the wound and through an exit site to facilitate discharge of serosanguinous fluid via suction. As is the case with any such catheter, skin flora have access to the wound along the length of the drain. Given sufficient levels of microorganism migration, colonization, and growth, an infection can result. A potential measure to prevent migration of flora along the catheter is a coating containing an antimicrobial agent such as silver sulfadiazine. Such a coating would be expected to significantly decrease the number of microorganisms present on the drain surface. Herein, such a coating is applied to a wound drain and tested for antimicrobial activity with the objective of observing antimicrobial efficacy versus an uncoated wound drain.
Channel style silicone wound drains (Parker Hannifin, Merrillville, IN) were cleaned and oxidized via oxygen plasma treatment, followed by further plasma treatment to enhance surface characteristics. Following plasma treatment, the drains were coated with a poly(vinyl) alcohol coating containing silver sulfadiazine, followed by cross linking via acetal formation and curing. The drains were then packaged and sterilized via gamma irradiation, followed by two different types of antimicrobial testing.
Antimicrobial activity was tested using the standard Kirby-Bauer method, by pressing cross-sections of drains into Mueller Hinton agar inoculated with various organisms and observing zones of inhibition versus positive and negative controls after incubation for 16 hours. Additionally the exterior portions of the drains were removed to test coating of the channels. All coated wound drain segments showed considerable zones of inhibition, ranging from 11 – 21 mm for the full drain segments, and significantly, as high as 7 mm for the segments containing the interior channel portion only.
Time-kill studies were performed in the following manner. Both coated and uncoated wound drain segments were immersed in a nutrient solution composed of 2% tryptic soy broth (TSB) in phosphate buffered saline (PBS) contaminated with approximately 106 colony forming units (CFU)/mL of the following organisms: S. aureus, P. aeruginosa, E. coli, and C. albicans. Following incubation at 25 °C, aliquots were removed at days 3, 5, and 7, diluted, plated, and enumerated. Results show a minimum 4 log reduction for the coated drains versus uncoated controls.
A wound drain containing a hydrogel coating with silver sulfadiazine showed pronounced efficacy against common pathogenic organisms versus an uncoated control drain. The results also demonstrate continued release of silver sulfadiazine throughout the test period.
Session: Emerging Technology Poster
Program Number: ETP087