Bacteria-free rinse water for endoscope disinfection

Most breaches of endoscope disinfection result from inadequate manual cleaning or improper use of disinfectants. This is a description of how a quality assurance program identified rinse water as a source of bacterial contamination and how it facilitated the introduction of a novel means of delivering rinse water of high purity.

Between 1996 and 2001, weekly samples were obtained from accessory and suction channels of endoscopes as well as the internal chambers of automated washing machines. Samples were processed for routine bacterial and mycobacterial culture.

Bacteria were isolated in 8.7% of samples collected between 1996 and 1998. Of 36 positive samples, 20 (54%) were Pseudomonas sp. Analysis of rinse water from pipework downstream from filters demonstrated high growth of Pseudomonas sp, suggesting biofilm within piping was contaminating rinse water. A system of hot water flushing of pipework was developed that maintains a temperature above 60 degrees C for 60 minutes on a daily basis. This resulted in a consistently low level of bacterial contamination.

This report demonstrates the value of a quality assurance program for endoscope disinfection and shows how rinse water may contaminate disinfected endoscopes. A system of hot water purging of the rinse water delivery system markedly reduces this contamination.