The effectiveness of sterilization for flexible ureteroscopes: A real-world study


      There are no guidelines or quality benchmarks specific to ureteroscope reprocessing, and patient injuries and infections have been linked to ureteroscopes. This prospective study evaluated ureteroscope reprocessing effectiveness.


      Reprocessing practices at 2 institutions were assessed. Microbial cultures, biochemical tests, and visual inspections were conducted on sterilized ureteroscopes.


      Researchers examined 16 ureteroscopes after manual cleaning and sterilization using hydrogen peroxide gas. Every ureteroscope had visible irregularities, such as discoloration, residual fluid, foamy white residue, scratches, or debris in channels. Tests detected contamination on 100% of ureteroscopes (microbial growth 13%, adenosine triphosphate 44%, hemoglobin 63%, and protein 100%). Contamination levels exceeded benchmarks for clean gastrointestinal endoscopes for hemoglobin (6%), adenosine triphosphate (6%), and protein (100%). A new, unused ureteroscope had hemoglobin and high protein levels after initial reprocessing, although no contamination was found before reprocessing.


      Flexible ureteroscope reprocessing methods were insufficient and may have introduced contamination. The clinical implications of residual contamination and viable microbes found on sterilized ureteroscopes are unknown. Additional research is needed to evaluate the prevalence of suboptimal ureteroscope reprocessing, identify sources of contamination, and determine clinical implications of urinary tract exposure to reprocessing chemicals, organic residue, and bioburden. These findings reinforce the need for frequent audits of reprocessing practices and the routine use of cleaning verification tests and visual inspection as recommended in reprocessing guidelines.

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        • Ofstead C.L.
        • Wetzler H.P.
        • Doyle E.M.
        • Rocco C.K.
        • Visrodia K.H.
        • Baron T.H.
        • et al.
        Persistent contamination on colonoscopes and gastroscopes detected by biologic cultures and rapid indicators despite reprocessing performed in accordance with guidelines.
        Am J Infect Control. 2015; 43: 794-801
        • Bommarito M.
        • Thornhill G.
        • Morse D.
        A multi-site field study evaluating the effectiveness of manual cleaning of flexible endoscopes with an ATP detection system.
        Am J Infect Control. 2013; 41: S24
        • Saliou P.
        • Le Bars H.
        • Payan C.
        • Narbonne V.
        • Cholet F.
        • Jézéquel J.
        • et al.
        Measures to improve microbial quality surveillance of gastrointestinal endoscopes.
        Endoscopy. 2016; 48: 704-710
        • Alfa M.J.
        • Olson N.
        • Murray B.L.
        Comparison of clinically relevant benchmarks and channel sampling methods used to assess manual cleaning compliance for flexible gastrointestinal endoscopes.
        Am J Infect Control. 2014; 42: e1-5
        • Ofstead C.L.
        • Wetzler H.P.
        • Eiland J.E.
        • Heymann O.L.
        • Held S.B.
        • Shaw M.J.
        Assessing residual contamination and damage inside flexible endoscopes over time.
        Am J Infect Control. 2016; 44: 1675-1677
        • Ofstead C.L.
        • Doyle E.M.
        • Eiland J.E.
        • Amelang M.R.
        • Wetzler H.P.
        • England D.M.
        • et al.
        Practical toolkit for monitoring endoscope reprocessing effectiveness: identification of viable bacteria on gastroscopes, colonoscopes, and bronchoscopes.
        Am J Infect Control. 2016; 44: 815-819
        • Bajolet O.
        • Ciocan D.
        • Vallet C.
        • de Champs C.
        • Vernet-Garnier V.
        • Guillard T.
        • et al.
        Gastroscopy-associated transmission of extended-spectrum beta-lactamase-producing Pseudomonas aeruginosa.
        J Hosp Infect. 2013; 83: 341-343
        • Epstein L.
        • Hunter J.C.
        • Arwady M.A.
        • Tsai V.
        • Stein L.
        • Gribogiannis M.
        • et al.
        New Delhi metallo-β-lactamase-producing carbapenem-resistant Escherichia coli associated with exposure to duodenoscopes.
        JAMA. 2014; 312: 1447-1455
        • Kovaleva J.
        • Degener J.E.
        • van der Mei H.C.
        Methylobacterium and its role in health care-associated infection.
        J Clin Microbiol. 2014; 52: 1317-1321
        • Wendelboe A.M.
        • Baumbach J.
        • Blossom D.B.
        • Frank P.
        • Srinivasan A.
        • Sewell C.M.
        Outbreak of cystoscopy related infections with Pseudomonas aeruginosa: New Mexico, 2007.
        J Urol. 2008; 180 (discussion 92): 588-592
        • Wendorf K.A.
        • Kay M.
        • Baliga C.
        • Weissman S.J.
        • Gluck M.
        • Verma P.
        • et al.
        Endoscopic retrograde cholangiopancreatography-associated AmpC Escherichia coli outbreak.
        Infect Control Hosp Epidemiol. 2015; 36: 634-642
        • Guy M.
        • Vanhems P.
        • Dananché C.
        • Perraud M.
        • Regard A.
        • Hulin M.
        • et al.
        Outbreak of pulmonary Pseudomonas aeruginosa and Stenotrophomonas maltophilia infections related to contaminated bronchoscope suction valves, Lyon, France.
        Euro Surveill. 2014; 2016: 21
        • Chang C.L.
        • Su L.H.
        • Lu C.M.
        • Tai F.T.
        • Huang Y.C.
        • Chang K.K.
        Outbreak of ertapenem-resistant Enterobacter cloacae urinary tract infections due to a contaminated ureteroscope.
        J Hosp Infect. 2013; 85: 118-124
        • Food and Drug Administration
        MAUDE adverse event report: Karl Storz Endovision Karl Storz Flexible Ureteroscope.
        2007 (MDR 867654)
        • Food and Drug Administration
        MAUDE adverse event report: Stryker URT-7000S Flexible Ureteroscope.
        2014 (MDR 3748403)
        • Food and Drug Administration
        MAUDE adverse event report: Olympus Medical Systems Corporation Olympus OES Cystonephrofiberscope.
        2010 (MDR 1853303, 1853287, 1853286, 1853285)
        • Carey R.I.
        • Martin C.J.
        • Knego J.R.
        Prospective evaluation of refurbished flexible ureteroscope durability seen in a large public tertiary care center with multiple surgeons.
        Urology. 2014; 84: 42-45
        • Kramolowsky G.
        • McDowell Z.
        • Moore B.
        • Booth B.A.
        • Wood N.L.
        Cost analysis of flexible ureteroscope repairs: evaluation of 655 procedures in a community-based practice.
        J Endourol. 2016; 30: 254-256
        • User H.M.
        • Hua V.
        • Blunt L.W.
        • Wambi C.
        • Gonzalez C.M.
        • Nadler R.B.
        Performance and durability of leading flexible ureteroscopes.
        J Endourol. 2004; 18: 735-738
        • Olympus America: Medical
        Instructions for use: OES Uretero-Reno Fiberscope Type P5.
        Olympus Corporation, Center Valley (PA)2006
        • Olympus America: Medical
        Instructions for use: Uretero-Reno Videoscope Type V.
        Olympus Corporation, Center Valley (PA)2008
        • Olympus America: Medical
        Instructions for use: Uretero-Reno Fiberscope URF-P6, URF-P6R.
        Olympus Corporation, Center Valley (PA)2014
        • PENTAX Medical Company
        Instructions for use: Uretereno Fiberscopes FUR-9P, FUR-10P, FUR-13P2.
        Hoya Corporation, Tokyo (Japan)2013
        • Association for the Advancement of Medical Instrumentation
        • American National Standards Institute
        ANSI/AAMI ST91: 2015, flexible and semi-rigid endoscope processing in health care facilities.
        Association for the Advancement of Medical Instrumentation, Arlington (VA)2015: 1-70
        • Association of Perioperative Registered Nurses
        Guideline for processing flexible endoscopes.
        in: Sterilization and disinfection. AORN, Denver (CO)2016: 675-758
        • Alfa M.J.
        • Fatima I.
        • Olson N.
        Validation of adenosine triphosphate to audit manual cleaning of flexible endoscope channels.
        Am J Infect Control. 2013; 41: 245-248
        • Alfa M.J.
        • Olson N.
        • Degagne P.
        • Simner P.J.
        Development and validation of rapid use scope test strips to determine the efficacy of manual cleaning for flexible endoscope channels.
        Am J Infect Control. 2012; 40: 860-865
        • Ofstead C.L.
        • Wetzler H.P.
        • Heymann O.L.
        • Johnson E.A.
        • Eiland J.E.
        • Shaw M.J.
        Longitudinal assessment of reprocessing effectiveness for colonoscopes and gastroscopes: results of visual inspections, biochemical markers, and microbial cultures.
        Am J Infect Control. 2017; 45: e26-33
        • Visrodia K.H.
        • Ofstead C.L.
        • Yellin H.L.
        • Wetzler H.P.
        • Tosh P.K.
        • Baron T.H.
        The use of rapid indicators for the detection of organic residues on clinically used gastrointestinal endoscopes with and without visually apparent debris.
        Infect Control Hosp Epidemiol. 2014; 35: 987-994
        • Herve R.C.
        • Keevil C.W.
        Persistent residual contamination in endoscope channels; a fluorescence epimicroscopy study.
        Endoscopy. 2016; 48: 609-616
        • Food and Drug Administration
        MAUDE adverse event report: Karl Storz Karl Storz, 7.5 FR Flexible Ureteroscope.
        2016 (MDR 6099529)
        • Storms L.
        Urgent medical device safety notice: Olympus uretero-reno fiberscope.
        Olympus Corporation of the Americas, Center Valley (PA)2016