Infections in Endoscopy - Clinical Literature Review


Real rates of infections in endoscopy

Title: Rates of Infection after Colonoscopy and OGD’s in ASC’s in the USA
Authors: Peiqi Wang, Tim Xu, Saowanee Ngamruengphong, Martin A Makary, Anthony Kalloo, Susan Hutfless
Date: May, 2018

Study Overview
This study aimed to estimate the rates of infections after colonoscopy and OGD performed in emergency departments in the USA. They tracked infection-related emergency department visits and unplanned in-patient admissions within 7 and 30 days after the procedures, examined infection sites and organisms and analysed predictors of infections. The study concluded that postendoscopic infections are more common than previously thought and vary widely by facility.

The rates of postendoscopy infections per 1000 procedures within 7 days were:

  • 1.1 for screening Colonoscopies
  • 1.6 for non-screening Colonoscopies
  • 3.0 for OGD


Following guidelines ensures a safe scope

Title: Longitudinal assessment of reprocessing effectiveness for colonoscopes and gastroscopes
Authors: Ofstead CL, Wetzler HP, Heymann OL, Johnson EA, Eiland JE, Shaw MJ.
Date: May, 2018

Study Overview
This longitudinal study involved visual inspections with a borescope, microbial cultures, and biochemical tests to identify endoscopes in need of further cleaning or maintenance. Three assessments were conducted over a 7-month period.


  • At final assessment, all endoscopes (N = 20) had visible irregularities
  • Of 12 (60%) endoscopes with microbial growth, 4 had no growth until after 48 hours
  • Similar proportions of control and intervention endoscopes (~20%) exceeded postcleaning biochemical test benchmarks
  • Researchers observed fluid (95%), discoloration, and debris in channels


Reprocessing errors are ongoing and numerous

Title: Endoscope Reprocessing Methods: A Prospective Study on the Impact of Human Factors and Automation
Authors: Ofstead CL, Wetzler HP, Snyder AK, Horton RA.
Date: May, 2018

Study Overview
The main cause of endoscopy-associated infections is failure to adhere to reprocessing guidelines. The purpose of this multisite, observational study was to evaluate reprocessing practices, employee perceptions, and occupational health issues. Data were collected utilizing interviews, surveys, and direct observation.

Observers documented guideline adherence, with only 1.4% of endoscopes reprocessed using manual cleaning methods with automated high-level disinfection versus 75.4% of those reprocessed using an automated endoscope cleaner and reprocessor. The full publication shows other interesting findings:

  • Multiple steps were missed 45% of the time
  • Failure rate of the 2 most important steps occurred >50%
    • Incomplete brushing (57%)
    • Not using forced Air (55%)


Global review of duodenoscope contamination issue

Title: Safely Reprocessing Duodenoscopes: Current Evidence and Future Directions
Authors: Zachary A Rubin, Stephen Kim, Adarsh M Thaker, V Raman Muthusamy
Date: July, 2018

Study Overview
This review summarises the most salient current research on duodenoscope-associated outbreaks and reprocessing, and aims to provide clinicians with practical information applicable to their practice.


  • 32 outbreaks involving almost 400 patients (Jan 2000 – Dec 2017)
  • The most common pathogens were Klebsiella pneumoniae and Pseudomonas aeruginosa
  • Defective institutional cleaning practices were described in five reports, no defects were described in eight, and cleaning practices were not described in the remaining 19


15% of duodenoscopes contaminated according to a study

Title: High Prevalence Rate of Digestive Tract Bacteria in Duodenoscoopes: A Nationwide Study
Authors: Arjan W Rauwers, Anne F Voor in ’t holt, Jolanda G Buijs, Woutrinus de Groot, Bettina E Hansen, Marco J Bruno, Margreet C Vos
Date: February, 2018

Study Overview
This nationwide cross-sectional study aimed to determine the prevalence of bacterial contamination of reprocessed duodenoscopes in the Netherlands. All 73 Dutch ERCP centres were invited to sample ≥2 duodenoscopes. The results suggest that the present reprocessing and process control procedures are not adequate and safe.


  • Sixty-seven out of 73 centres (92%) sampled 745 sites of 155 duodenoscopes.
  • Ten different duodenoscope types from three distinct manufacturers were sampled including 69 (46%) Olympus TJFQ180V,43 (29%) Olympus TJF-160VR, 11 (7%) Pentax, ED34-i10T, 8 (5%) Pentax ED-3490TK and 5 (3%), Fujifilm ED-530XT8
  • Thirty-three (22%) duodenoscopes from 26 (39%) centres were contaminated (AM20)
  • On 23 (15%) duodenoscopes MGO were detected including Enterobacter cloacae, Escherichia coli, Klebsiella pneumonia and yeasts

Duodenoscope “attack rate” ~ 30%

Title: Independent Root Cause Analysis of Contributing Factors, Including Dismantling of 2 Duodenoscopes to an Outbreak of Multidrug-resistant Klebsiella Pneumoniae.
Authors: Arjan W. Rauwers, Annet Troelstra, Ad C. Fluit, Camiel Wissink, Arjo J. Loeve, Frank P. Vleggaar, Marco J. Bruno, Margreet C. Vos, Lonneke G.M. Bode, Jan F. Monkelbaan
Date: May, 2019

Study Overview
This article reports on the investigation after the outbreak of a multidrug-resistant Klebsiella pneumoniae (MRKP) related to 2 Olympus TJF-Q180V duodenoscopes. Reprocessing procedures were audited, and both duodenoscopes were fully dismantled to evaluate all potential contamination factors.


  • In total, 102 patients who had undergone an ERCP procedure from January to August 2015 were invited for screening. Cultures were available of 81 patients, yielding 27 MRKP infected or colonized patients
  • Ten patients developed a MRKP-related active infection
  • The duodenoscopes had attack rates (the number of infected or colonized cases/number of exposed persons) of 35% (17/49) and 29% (7/24)
  • The review revealed 4 major abnormalities:
    • miscommunication about reprocessing
    • undetected damaged parts
    • inadequate repair of duodenoscope damage
    • and duodenoscope design abnormalities, including the forceps elevator, elevator lever, and instrumentation port sealing