Years of experience and data from laboratory testing and both retrospective and prospective clinical studies have resulted in the evolution of endoscope reprocessing guidelines into their current set of refined and comprehensive instructions that are endorsed by several professional organizations. The conclusion that these current guidelines are safe and effective and do not require significant modifications is primarily based on the finding that, without exception, every documented case of exogenous infection resulting from a contaminated GI endoscope (or endoscopic accessory) identified as its cause a breach of at least one of the instructions published in these guidelines. Common failures or breaches in reprocessing protocols linked to disease transmission during GI endoscopy include improper cleaning, ineffective high-level disinfection or inappropriate use of a liquid chemical sterilant (LCS), and insufficient drying before storage.
Only a few reports of disease transmission via a GI endoscope or endoscopic accessory have been published. There are, nevertheless, some examples that are educational and warrant discussion to highlight the adverse outcomes that can result when reprocessing practices deviate from current endoscope reprocessing guidelines. For example, one report identified improper cleaning and ineffective high-level disinfection using a LCS as responsible for disease transmission during GI
endoscopy (Bronowicki et al, 1997). This report documented patient-to-patient transmission of the hepatitis C virus during colonoscopy due to failure to clean the endoscope's suction and biopsy channels using a brush as reprocessing guidelines emphasize. In addition, this report indicated that high-level disinfection of the colonoscope was ineffective because the colonoscope was immersed in 2% glutaraldehyde for only 5 minutes, guidelines recommending an immersion time of no less than 20 minutes not withstanding. This report also indicated that, although mechanically cleaned using a detergent, the biopsy forceps, like the colonoscope, were immersed in 2% glutaraldehyde and not steam sterilized as reprocessing guidelines recommend. (Also contributing to the possibility for disease transmission, the intravenous (IV) lines and needles used on patients discussed in this report were changed, but the syringes used to administer the IV medications were reused and not disposable and single use as guidelines for administration of IV medications recommend.)
Another report identified disease transmission as a result of ineffective high-level disinfection. This report documented patient-to-patient transmission of Campylobacter pylori during esophagogastroduodenoscopy (EGD) and biopsy due to exposure of the endoscope and its internal channels after cleaning with 70% alcohol for 3 minutes between patient procedures (Langenberg et al, 1990). Seventy percent alcohol is classified as an intermediate-level disinfectant—not a high-level disinfectant as recommended—and, therefore, its use is in violation of endoscope reprocessing guidelines. Disinfection, rather than sterilization, of the biopsy forceps used during EGD also reportedly contributed to the transmission of C. pylori.
Improper cleaning and ineffective high-level disinfection are not the only reported causes of exogenous infection during GI endoscopy. Insufficient drying of the endoscope has also been blamed for disease transmission. In one case, an outbreak of Pseudomonas aeruginosa and Enterobacteriaceae in patients undergoing endoscopic retrograde cholangio-pancreatography (ERCP) was reported (Streulens et al, 1993). Failure to dry the endoscope's channels, including the narrow elevator forceps raiser channel, with 70% alcohol followed by compressed or forced air after high-level disinfection (and water rinsing) was identified as the cause of the outbreak. Terminal drying of the endoscope's internal channels is recommended by reprocessing guidelines to prevent infection due to gram-negative waterborne bacteria and atypical mycobacteria that may be present in the water used to rinse the endoscope after high-level disinfection. Virtually every report that links patient infection to an inadequately dried GI endoscope contaminated with bacteria occurred during ERCP, suggesting that infection is based on the type of GI procedure performed, among other factors. All of these aforementioned reports underscore the importance ofstrict adherence to all of the recommended practices and steps provided in current endoscope reprocessing guidelines.
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