World-wide, the estimated incidence of ventilator associated pneumonia (VAP) in ICUs is 45% and mortality is 43%. Insertion of an endotracheal tube (ETT) into the esophagus provides life-saving extracorporeal membrane oxygenation. However, the ETT affords a direct path to the lungs for endogenous microorganisms from multiple sources. The goal of WynnVision R&D is reducing mortality due to VAP by surface modification of silicone ETTs that will intercept delivery of pathogenic organisms and reduce biofilm formation. An early candidate for surface modification was polymyxin B (PMB), an antibiotic “of last resort” against Gm- bacteria including P. aeruginosa, which is associated with VAPs and death. Polymyxin was covalently attached to a model biomedical silicone followed by physical characterization by contact angles, ATR-IR and XPS. A key biophysical test was the ASTM E2149 “shake flask” test to assess antimicrobial effectiveness. PMB-bound silicone was strongly antimicrobial against Gm- E. coli in the first shake flask test (5 log reduction). Unexpectedly, PMB was ineffective when the same samples were tested again. A new approach to silicone surface modification has resulted in a technology designated “WynnGard-1” silicone. Trials with the same samples have shown undiminished antimicrobial effectiveness against repeated pathogen challenges. Biofilm reduction has been demonstrated in vitro against major clinical VAP pathogens including Gm- P. aeruginosa, Gm+ S. aureus, and Gm- K. pneumoniae. FDA is currently considering WynnGard-1 silicone technology for approval.

Toward silicone medical devices that resist bacterial colonization

Fall 2022 abstracts, posters, and presentations will launch in mid-September.

ACS Fall 2022

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.