Multicenter study on gastroscope disinfection and sample survey of automated washer/disinfectors

Objective To select a practical and reliable method in cleaning and disinfecting endo-scope, and to investigate the efficacy of endoscope disinfection. Methods A study was done on the disinfection efficacy using or not using enzyme cleaning plus 2% glutaraldehyde immersion, and disinfection efficacy of automated washer/disinfectors for endoscopes at tertiary hospitals in Beijing. Results In 301 cases of en-doscopes cleaned with enzyme ( Epizyme rapid multi enzyme cleanse) and immersed in 2% glutaraldehyde for 7 minutes, culture was negative in 283 cases (94. 02% ) ; in 155 cases without enzyme cleaning but with immersion for 7 minutes in 2% glutaraldehyde, culture was negative in 137 cases (88. 39 % ). Taking 20 or less bacteria per endoscope as the eligibility criterion, there were 298(99.00% ) and 147(94. 84% ) cases eligible in enzyme treated and enzyme untreated group respectively , P 0.01. Sample survey of cleaning and disinfection efficacy of automated washer/disinfector : (1) Machine I in 35 cases, after cleaning and disinfection for 3 minutes, culture was negative in 4 cases ( 11. 43 % ) , taking 20 or less bacteria per endoscope as the eligibility criterion, 5 cases were eligible (14. 29%). (2) Machine II in 29 cases, after cleaning and disinfection for 3 minutes,culture was negative in 2 cases ( 6. 90% ) , taking 20 or less bacteria per endoscope as the eligibility criterion, 6 cases were eligible ( 20.69% ). (3) Machine II in 20 cases, after cleaning and disinfection for 6 minutes, culture was negative in 17 cases ( 85. 00% ) , taking 20 or less bacteria per endoscope as the eligibility criterion, 18 cases were eligible ( 90. 00% ) . All results of the auto-mated washer/disinfectors fell short of the sterilization standard. Conclusions Thorough cleaning of every part of the endoscope is necessary to ensure disinfection efficacy. The use of enzymes in the cleaning process enhances the cleanness; on that basis, immersion in 2% glutaraldehyde for 7 minutes achieves adequate sterilization. The currently employed home made automated washer/disinfector routine method, cleaning and disinfection for 3 or 6 minutes, is insufficient to attain the standard of safe disinfection of endoscope.