Tu1113 A BENCHTOP EVALUATION OF VARIOUS SUSPECTED BIOFILM RESERVOIRS WITHIN A DUODENOSCOPE

Abstract

Multidrug resistant organisms (MDRO) / carbapenem resistant enterobacteriaceae (CRE) have emerged as serious public health problems, particularly among immune compromised patients. It is now known that duodenoscopes may transmit MDRO due to biofilm buildup, which may explain prior CRE outbreaks with culture-negative duodenoscopes. However, the precise location of biofilm buildup has been the subject of speculation. Thus, we aimed to investigate various suspected biofilm reservoir locations & scenarios among key, hard-to-reach components of a duodenoscope. This was a cross sectional translational study. Two key duodenoscope components were investigated – accessory channel tubing in various states of distress, & elevator wire conduit (known as a sus pipe). These two components were chosen either because they can be damaged in routine clinical use (accessory channel tubing), or because of a recent design change where the channel is sealed with O-rings (sus pipe), which prevents high-level disinfection (HLD) of the channel. Additionally, both areas are known to be difficult / impossible to brush, especially the sus pipe. New accessory channel tubing was cut into 2-inch segments, & cultured immediately (negative control), after biofilm creation (positive control), or after distressing the tubing in various manners & undergoing suboptimal HLD without manual brushing. New sus pipe was also cut into 2-inch segments & underwent negative control, positive control, & suboptimal HLD without manual brushing. To distress the tubing, we employed 3 techniques to simulate one year’s worth of “worst case scenario” duodenoscope usage – intentional abrasion (by passing a half-bowed sphincterotome or a cleaning brush through the tubing 1,872 times), or intentional tubing puncture with a commonly used injection needle. Thereafter, we created biofilm by mixing artificial test soil ATS 2015 with organisms that favor biofilm formation (E fecalis, P aeruginosa, & K pneumoniae), & enriched with defibrinated sheep blood. Each test segment was incubated for 5 days at 35°C, then rinsed with sterile water. Positive control segments underwent immediate sonication & culturing, while test segments underwent suboptimal HLD (a simulated HLD cycle without manual brushing), then sonicated & cultured. Culture x72h & Interpretation were performed in a blinded manner. Each of the testing arms was repeated in triplicate. The results are shown in table 1&2 (images) 1. Distressed tubing does not appear to promote biofilm formation even in a simulated “worst case scenario” of heavy usage, & suboptimal HLD