Improper positioning of the elevator lever of duodenoscopes may lead to sequestered bacteria that survive disinfection by automated endoscope reprocessors

摘要

Graphical Abstract Display Omitted Highlights " Simulated-use testing showed that bacteria in the presence of organic material may survive liquid chemical sterilization and HLD after one round of reprocessing if the duodenoscope elevator lever is in the horizontal position. " The expected 6 Log 10 kill of vegetative Enterococcus faecalis and Escherichia coli may not be achieved when bacteria were sequestered under the horizontal duodenoscope lever in the presence of organic material. " There may be a very low margin of safety if bacteria and organic material become sequestered under the duodenoscope elevator lever in the horizontal position. Background Some outbreaks associated with contaminated duodenoscopes have been attributed to biofilm formation. The objective of this study was to determine whether bacteria within an organic matrix could survive if the elevator lever was improperly positioned in the automated endoscope reprocessor (AER) after 1 round of reprocessing. Methods Duodenoscope lever cavities with an open or sealed elevator wire channel were inoculated with 6-7 Log 10 of both Escherichia coli and Enterococcus faecalis in ATS2015 (Healthmark Industries, Fraser, MI) and dried for 2 hours. The duodenoscopes with the lever in the horizontal position were processed through 2 makes of AERs. The cavity was sampled using a flush-brush-flush method to determine the quantity of surviving bacteria. Results E faecalis (range, 21-6 Log 10 CFU) and E coli (range, 0-3 Log 10 CFU) survived disinfection of sealed or unsealed elevator wire channel duodenoscopes in 2 different AERs with and without cleaning cycles. Conclusion If bacteria in organic residue are under the improperly positioned lever, then just 1 round of use is sufficient for bacteria to survive both liquid chemical sterilization and liquid chemical HLD regardless of whether or not the AER had a cleaning cycle.