Wet chemical silver treatment of endotracheal tubes to produce antibacterial surfaces.

Mechanically ventilated patients in hospitals are subjected to an increased risk of acquiring nosocomial pneumonia that sometimes has a lethal outcome. One way to minimize the risk could be to make the surfaces on endotracheal tubes antibacterial. In this study, bacterial growth was inhibited or completely prevented by silver ions wet chemically and deposited onto the tube surface. Through the wet chemical treatment developed here, a surface precipitate was formed containing silver chloride and a silver stearate salt. The identity and morphology of the surface precipitate was studied using x-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, scanning electron microscopy, and x-ray powder diffraction. Leaching of silver ions into solution was examined, and bacterial growth on the treated surfaces was assayed using Pseudomonas aeruginosa wild type (PAO1) bacteria. Furthermore, the minimum inhibitory concentration of silver ions was determined in liquid- and solid-rich growth medium as 23 and 18 microM, respectively, for P. aeruginosa.