Sampling and endoscopes

Dr Tony Speer 1

1 Royal Melbourne Hospital, Parkville, Vic, 3050.


Outbreaks of pseudomonas cholangitis after ERCP in the 1980s exposed a flaw in reprocessing – a failure to adequately dry endoscopes. Alcohol flush and forced air drying was added to the guidelines and the outbreaks resolved. Transmission of small numbers of enteric and environmental bacteria remains a problem, surveillance cultures are positive in 2-4% of patient ready gastroscopes, colonoscopes and duodenoscopes. Transmission of antibiotic sensitive bacteria is difficult to detect and has had few clinical consequences. However, transmission of CPE is followed by colonisation and in some patients clinical infections with substantial morbidity and mortality. In Western countries the emergence of CPE has been followed, usually within a few years, by outbreaks of endoscopy associated CPE infection. The epidemiology of outbreaks, a single species transmitted on multiple occasions over several months suggests biofilms on endoscopes are acting as a reservoir for CPE. Scanning electron microscopy studies have found biofilm on most channels removed from gastroscopes and colonoscopes during repairs. Inadequate drying and/or cleaning and occult endoscope defects increase biofilm formation and all have been reported as causes of outbreaks of CPE. Reviews of surveillance cultures of endoscopes in Australia, NZ and USA have found surveillance identifies breaches in reprocessing protocols and occult endoscope defects before adverse clinical outcomes occur. Surveillance cultures have been recommended in Australia since 1995 and are now recommended in most countries. The FDA, CDC, and ECRI have recommended surveillance cultures in response to the recent CPE outbreaks. Surveillance cultures are a quality control marker of the adequacy and completeness of the entire cleaning and disinfection process and the structural integrity of the endoscope.

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