Cleaning and disinfection of fiberoptic endoscopes: evaluation of glutaraldehyde exposure time and forced-air drying

Abstract

Several alternative schedules of cleaning and disinfection of flexible fiberoptic endoscopes were evaluated during actual use in paired endoscopy suites. Thorough mechanical cleaning with detergent and alcohol was compared with the same cleaning with the addition of 5-, 10-, or 20-min immersion of the endoscope insertion tube in 2% alkaline glutaraldehyde solution. Endoscopes were cultured quantitatively and qualitatively for aerobic bacteria at three different times relative to procedures: after use, immediately after cleaning alone or cleaning plus disinfection, and after storage unused in a cabinet for 20-72 h. Cleaning plus glutaraldehyde immersion for 5 min significantly reduced bacterial contamination both immediately and after storage when compared with cleaning alone. Results of cleaning plus 10- and 20-min glutaraldehyde immersion were not statistically different from cleaning plus 5-min glutaraldehyde immersion. The addition of forced-air drying following disinfection significantly reduced bacterial contamination following storage when compared with storage without previous drying. Cleaning plus brief (5-20 min) glutaraldehyde immersion significantly reduced bacterial contamination of endoscopes when compared with cleaning alone (p less than 0.001) and, when combined with forced-air drying before storage, resulted in 59/63 (94%) negative endoscope cultures by the methods used in this study. These measures do not ensure sterility, but are superior to mechanical cleaning alone and sufficiently practical to be used routinely without undue interruption of busy endoscopy schedules.