Gastrointestinal endoscopes: a need to shift from disinfection to sterilization?

More than 10 million gastrointestinal endoscopic procedures areperformedannually in theUnitedStates fordiagnosticpurposes, therapeutic interventions, or both.1 Because gastrointestinalendoscopescontactmucosal surfaces,useofacontaminated endoscope may lead to patient-to-patient transmission of potential pathogens with a subsequent risk of infection.1 In this issue of JAMA, Epstein and colleagues2 report findings from their investigation of a cluster ofNewDelhimetalloβ-lactamase (NDM)–producingEscherichia coliassociatedwith gastrointestinal endoscopy that occurred from March 2013 to July2013 inasinglehospital in northeastern Illinois. During the 5-month period, 9 patients with positive cultures for NDM-producing E coli were identified, and a case-control study demonstrated that a history of undergoing an endoscopic procedure at this specific hospital was strongly associatedwithcasesofNDM-producingEcoli.Culturesobtainedfrom the endoscope used on 5 of the case patients yielded anNDMproducingE coli from the elevator channel. The elevator channel is unique to side-viewing endoscopes, most often used to perform endoscopic retrograde cholangiopancreatography (ERCP). The elevator has a separate channel and provides orientation of catheters, guidewires, and accessories into the endoscopicvisual field.Thischannel iscomplex indesignandmay bemore difficult to disinfect completely. TheEcoli isolatewashighlyrelated(>92%)toallcasepatient isolatesbypulsed-fieldgelelectrophoresis.Endoscopereprocessingprocedureswerereviewedandnolapseswereidentified.Further, theautomatedendoscopereprocessor (AER)wasfunctioning correctly and the duodenoscopes were not damaged. The facilitynotified the226patientswhohadpotential exposure to aculture-positiveendoscope.Twenty-sevenadditionalcasepatientswere identifiedbyactivesurveillancewhowerecolonized andhadbeenexposed to aduodenoscope.No additional cases were identifiedafter thehospital changed its endoscope reprocessing from automated high-level disinfection with orthophthalaldehyde to gas sterilizationwith ethylene oxide. The key concern raised by this study is whether current US endoscope reprocessing guidelines are adequate to ensure a patient-safe gastrointestinal endoscope (one devoid of potential pathogens) or if endoscopeswith their long, narrow channels, right-angle turns,difficult tocleananddisinfectcomponents, andheavymicrobial contamination impossible to reliably high-level disinfect. To examine this concern and offer recommendations, understanding current knowledge on endoscope reprocessing is necessary. First, endoscopes are semicritical devices, which contact mucousmembranesornonintact skin,andrequireat leasthighleveldisinfection.3,4High-leveldisinfectionachievescomplete eliminationof allmicroorganisms, except for smallnumbersof bacterial spores. Because flexible gastrointestinal endoscopic instruments are heat labile, only high-level disinfection with chemical agents or low-temperature sterilization technologies arepossible.3However, no low-temperature sterilization technology is US Food andDrug Administration (FDA)–cleared for gastrointestinal endoscopes such as duodenoscopes. Second,more health care–associated outbreaks and clusters of infection have been linked to contaminated endoscopes thantoanyothermedicaldevice.3,5However,untilnow, these episodes have been traced todeficient practices such as inadequate cleaning, inappropriate disinfection, and damagedendoscopesor flaws in thedesignofendoscopesorAERs.3 In addition, reprocessing failures have led to patient notificationsandblood-bornepathogentesting indozensof instances.6 Third, evidence-based endoscope reprocessing guidelines havebeenpreparedbyprofessionalorganizationsand theCenters for Disease Control and Prevention (CDC). Although some datahavedemonstratedthat rigorousadherencetotheseguidelineswill result in a patient-safe endoscope,3,4 other data have demonstratedthatallof thestepsassociatedwithmanualendoscopereprocessingarerarelyperformedandsomeessentialsteps (eg,brushingallendoscopechannelsandcomponents)arecommonlyskipped.7Endoscopereprocessingwasimprovedwiththe use of AERs becausemost stepswere automated.7 Fourth,endemic transmissionof infectionsassociatedwith gastrointestinal endoscopes may be unrecognized due to inadequate surveillance of outpatient procedures, long lag time between colonization and infection, and a low frequency of clinical infection. Additionally, the risk for some procedures mightbehigher thanothers inwhichnormally sterile areas are contaminated. In the cluster of cases identified by Epstein et al, thepresenceofanunusualpathogen(NDM-producingEcoli) prompted an investigation and subsequent recognition that duodenoscopes were the source of the case patient isolates.2 Fifth, themarginof safetyassociatedwith reprocessingendoscopes isminimal.Endoscopesareheavilycontaminatedwith microbes. The internal channel of gastrointestinal endoscopes may contain 108-10 (8-10 log10) enteric microorganisms.8 The cleaning step in endoscope reprocessing results in a 4 to 6 log10 reduction of microbes and the high-level disinfection step results inanother4to6 log10 reductionofmycobacteria, fora total 8 to 12 log10 reduction ofmicrobes.9 Thus, themargin of safety associated with cleaning and high-level disinfection of gastroRelated article page 1447 Opinion