The Study of a Contaminated Colonoscope

Abstract

Gastrointestinal (GI) endoscopy departments may sample their flexible endoscopes microbiologically, either after reprocessing or prolonged storage, as part of a comprehensive quality assurance program.1World Gastroenterology Organization. WGO-OMGE and OMEDPractice guideline: endoscope disinfection.http://www.omed.org/downloads/pdf/guidelines/wgo_omed_endoscope_disinfection.pdfGoogle Scholar Although a controversial practice that generally is not recommended, except possibly during an outbreak investigation, the periodic monitoring of a GI endoscope may be performed to evaluate the effectiveness of an endoscope-reprocessing procedure, or to determine the cause of an identified infection. Although the lack of surveillance cultures to grow bacteria does not confirm the sterility of the endoscope, bacterial growth in any one of these collected samples likely indicates endoscope contamination and, therefore, the potential for disease transmission. Microbiological sampling of a GI endoscope can yield insightful data, but the shortcomings of this practice are significant and its applications and usefulness are limited. For example, the techniques used to collect microorganisms from an endoscope's internal channels and other sampled surfaces have not been standardized and their methodologies not validated, which can cause the results of surveillance cultures to be unreliable and inaccurate.In accordance with its standard operating procedures, a GI endoscopy department in the southwest United States each month microbiologically samples for bacterial contamination one of its several models of reprocessed GI endoscopes. On one occasion in the winter of 2009, some of the cultures collected from the sampled surfaces of a stored (and randomly selected) colonoscope, known as the test colonoscope, yielded positive growth for both patient-borne and environmental bacteria—a finding that raised the specter of disease transmission. In response, this GI endoscopy department initiated an investigation to evaluate the risk of infection during GI endoscopy and assess whether this finding might harbinger a true or pseudo-infection or outbreak. This investigation included an inspection of this GI department's endoscope-reprocessing practices.Although causally associating disease transmission with a specific GI endoscope and reprocessing breach can for a number of reasons be challenging, if rare, the medical records of patients nonetheless were examined during this investigation to evaluate whether any infections might be attributable to an improperly reprocessed GI endoscope. These records were reviewed, for example, to determine whether a patient with no other risk factors for infection and known previously not to have been infected with the hepatitis C virus had tested positive for this virus' antibodies after undergoing colonoscopy in this GI endoscopy department.2Bronowicki J.P. Venard V. Botté C. et al.Patient-to-patient transmission of hepatitis C virus during colonoscopy.N Engl J Med. 1997; 337 ([Erratum appears in: N Engl J Med 2001;344:392.]): 237-240Crossref PubMed Scopus (401) Google Scholar Because surveillance cultures collected from a colonoscope the previous month yielded no growth, only those patients on whom a GI endoscope was used during the past 4 weeks (during which time a new staff member was hired to reprocess endoscopes) were considered to be at an increased risk of infection. Although the potential for any of this GI endoscopy department's upper and lower GI endoscopes to be contaminated after reprocessing was not ruled out, this investigation focused on the reprocessing of its colonoscopes.MethodsThe suction channel, suction valve, insertion tube's exterior surface, and water-jet (or auxiliary water) channel of the test colonoscope were sampled in accordance with published microbiological techniques and this GI endoscopy department's standard operating procedures.3Standard test method for determination of effectiveness of cleaning processes for reusable medical instruments using a microbiologic method (simulated use test). ASTM International, West Conshohocken, PA2008https://doi.org/10.1520/E2314-03R08Crossref Google Scholar The genus and, when possible, both species and strain of each of the cultured bacteria were determined, to evaluate their epidemiology, mode of transmission, pathogenicity and reservoir, or source. The same surfaces of a second randomly selected colonoscope, known as the positive control because it had just been used during a procedure but had not yet been reprocessed (and, therefore, would be expected to be contaminated), were similarly sampled using these same microbiological techniques and procedures. Providing a reference for contamination, a positive control shows the specific types of bacteria that may contaminate the colonoscope during a routine procedure. It also confirms that the sampling techniques effectively recovered microorganisms from the endoscope's surfaces. If samples collected from this positive control were to yield no growth, however, then understanding that the colon's natural flora (or, indigenous microbiota) contain bacteria, this nil result would show, for example, that the sampling techniques are faulty, or, among other possible errors, that the culture media might have expired and no longer support bacterial growth invalidating the results.The same respective surfaces of a third randomly selected colonoscope used by this GI endoscopy department, known as the negative control because it had been sterilized using ethylene oxide gas before this study and, therefore, as its name suggests, should yield no growth, were similarly sampled using these same microbiological techniques and procedures. A negative control shows, in part, whether the sampling, assay, and microbiological techniques, and the handling of the endoscopes by staff, are aseptic as required. If samples collected from the negative control yield growth, then, similarly, one or more of the microbiological techniques and procedures are faulty (eg, the collected samples were contaminated during handling in the microbiology laboratory or, alternatively, the sterilization process could be ineffective), a finding that also would invalidate the results. The samples collected from these 3 colonoscopes were assayed exclusively for bacteria, not viruses, because bacteria are easy to culture and their growth is often a reliable indicator of, in addition to an endoscope-reprocessing breach, contamination of the endoscope with other microorganisms, too, including viruses (and fungi).4Queensland HealthEndoscope reprocessing Module 6.4: microbiological testing.http://www.health.qld.gov.au/EndoscopeReprocessing/module_6/6_4.aspGoogle ScholarSeveral environmental surfaces, including the tap water and a sink's faucet aerator, both of which are used by this GI endoscopy department to rinse the colonoscope after high-level disinfection, which is performed manually, also were sampled microbiologically, as were the hands and fingernails of staff members, including a recently hired staff member who, along with others, handled the 3 colonoscopes sampled and studied during this investigation. The determination not only of a potentially infectious bacterium's specific genus and species (and strain), but also source (or potential reservoir) is important to identify the infection-control breach and to prescribe effective measures to prevent disease transmission.5Muscarella L.F. Evaluation of the risk of transmission of bacterial biofilms and Clostridium difficile during gastrointestinal endoscopy.Gastroenterol Nurs. 2010; 33: 28-35Crossref PubMed Scopus (11) Google Scholar (Not performed during this investigation, which is fictional, was an inspection of this GI endoscopy department's quality-assurance documentation. Such an audit is recommended, however, and should be conducted periodically to determine, for example, whether available for training and teaching are model-specific standard operating procedures instructing staff members how to reprocess each of the several models of GI endoscopes in inventory properly.)ResultsThe bacteria sampled from the test colonoscope and from the positive control are displayed in Table 1 and Supplementary Table 1, respectively. The insertion tube's exterior of both the negative control and the test colonoscope yielded Staphylococcus aureus (this result in not displayed in the Tables), the same strain of which also was cultured from the fingernails of the newly hired staff member. Samples from the sink's faucet aerator and tap water yielded Pseudomonas aeruginosa, Mycobacterium avium-intracellulare (MAI), and Klebsiella pneumonia; these same strains were also cultured from the test colonoscope (Table 1). None of these 3 bacteria was sampled from the positive control (Supplementary Table 1). No other environmental surfaces yielded growth of any of these 3 types of bacteria or of this specific strain of S aureus. Further, this investigation found that for the past month, although required by manufacturers' instructions, this GI endoscopy department had not been performing any of the following requisite practices: (1) routinely monitoring the concentration of the re-used high-level disinfectant; (2) leak testing the GI endoscope after each procedure; and (3) reprocessing the colonoscope's suction valve and water-jet channel after each procedure.Table 1Bacteria Sampled From the Test Colonoscope, Examples of Common Sources of These Bacteria, the Sampled Surfaces Found to Be Contaminated, and the Likely Reprocessing Breach Responsible for the ContaminationBacteriumExamples of common sourcesSampled surfaces from the endoscope and environment found to be contaminatedLikely reprocessing breach responsible for the contamination of the colonoscope with bacteriaS aureusSkin, handsMoist environments: countertops, surfacesExterior of colonoscope's insertion tubeFingernails of staff memberImproper handling of the endoscope after reprocessingImproper hand washing, hand hygieneP aeruginosaSkin, handsMoist environments: water, sinks, faucet aeratorsColonoscope's water-jet channelTap water, sink's faucet aeratorRinsing the reprocessed endoscope with contaminated waterInadequate drying of the endoscopeK pneumoniaSkin, handsMoist environments: water, sinksLower GI tract (normal flora)Exterior of colonoscope's insertion tube, suction channelTap water, sink's faucet aeratorRinsing the reprocessed endoscope with contaminated waterInadequate drying of the endoscopeMAIMoist environments: water, sinksColonoscope's suction valveTap water, sink's faucet aeratorRinsing the reprocessed endoscope with contaminated waterInadequate drying of the endoscopeE faecalisLower GI tract (normal flora)Exterior of colonoscope's insertion tubeColonoscope's water-jet channelImproper cleaning and high-level disinfection of the endoscope Open table in a new tab DiscussionThis GI department's active surveillance program detected the contamination of a colonoscope, which initiated an investigation that identified several significant breaches in infection control. The sampling from both the test colonoscope and the positive control of Enterococcus faecalis (Table 1 and Supplementary Table 1)—this bacterium, similar to E coli and Bacteroides species, may be found in the colon's normal flora, and therefore the sampling of any from the positive control would not be an unexpected finding—suggests improper cleaning and high-level disinfection of the (test) colonoscope. Indicating an increased risk of patient-to-patient disease transmission during GI endoscopy, this result is consistent with the observation during this investigation that staff members failed to perform several endoscope-reprocessing practices properly, including to reprocess the colonoscope's suction valve and water-jet channel after each procedure as published guidelines (and this GI endoscopy department's standard operating procedures) require. Several reports have causally associated these significant endoscope-reprocessing breaches with the transmission of infectious agents, including the hepatitis C virus and the hepatitis B virus.3Standard test method for determination of effectiveness of cleaning processes for reusable medical instruments using a microbiologic method (simulated use test). ASTM International, West Conshohocken, PA2008https://doi.org/10.1520/E2314-03R08Crossref Google ScholarThe sampling of P aeruginosa, MAI, and K pneumonia, each of which may be found on moist environmental surfaces, from the test colonoscope (Table 1) and from the sink's faucet aerator and tap water, but not from either the positive or negative control, suggests that, in addition to inadequate terminal drying of the colonoscope's surfaces and channels, the tap water used to rinse the colonoscope after high-level disinfection was likely contaminated with these 3 bacteria. That the original source of the P aeruginosa and K pneumonia may have been the GI tract of a patient, but then subsequently colonized the sink's faucet aerator resulting in contamination of the tap water and the colonoscope during water rinsing, although an unlikely scenario, cannot be ruled out. MAI, however, is an atypical mycobacterium that is not transmitted from patient to patient, and its sampling from the sink's faucet aerator and tap water indicates either environmental site as its source. Further, the sampling from the test colonoscope of the identical strain of S aureus as from the fingernails of a newly hired staff member and the negative control suggests this staff member's fingernails (and hands) as this bacterium's source and the improper handling and recontamination of the colonoscope after reprocessing the specific infection-control breach.RecommendationsBased on the findings of this investigation, the following recommendations are provided to prevent disease transmission during GI endoscopy.First, properly clean and high-level disinfect the colonoscope (and other GI endoscopes) including the water-jet channel and both its suction and air/water valves, even if this channel and valves are not used during the procedure. Refer to published guidelines and the operator's manual of the endoscope's manufacturer for step-by-step reprocessing instructions.Second, leak test the GI endoscope after each patient procedure in accordance with the endoscope manufacturer's instructions, to ensure the endoscope's integrity and to prevent disease transmission. Perform this test before cleaning and brushing the endoscope's surfaces and channels using a detergent solution. Visually inspect the endoscope before additional reprocessing, to ensure none of its surfaces is torn or otherwise damaged. Ensure that the endoscope is serviced properly and maintained as recommended by its manufacturer.Third, after chemical immersion, thoroughly rinse all of the endoscope's surfaces and internal channels with bacteria-free or sterile water. (The use of fresh tap water for rinsing has not been shown to pose an increased risk of infection, provided the GI endoscope is dried as described in the next recommendation.)Fourth, dry the endoscope and its internal channels, both between patient procedures and before storage, using 70% alcohol and forced air, whether the rinse water is bacteria-free, extensively treated, sterile, or from a tap.Fifth, properly store the dried endoscope, hanging it vertically in a clean and well-ventilated (dry) storage cabinet or area, with the endoscope's valves and biopsy inlet cap removed. Monitor the number of days the GI endoscope remains in storage. Although corroborating data are scant, some studies suggest that a GI endoscope may be stored for as many as 7 days before requiring reprocessing before its re-use. The reprocessing of a side-viewing duodenoscope used during endoscopic retrograde cholangiopancreatography (and bronchoscope) is recommended before each use.Sixth, monitor the concentration of the re-used high-level disinfectant at least once a day, or more often, in accordance with the manufacturer's instructions, using an appropriately labeled chemical test strip (or other technology). Note that the labeling of most high-level disinfectants requires that its concentration be monitored before each re-use to ensure the effectiveness of its active ingredient.Seventh, handle the reprocessed endoscope with care to prevent damage. Wear (new and disposable) clean or sterile gloves to prevent recontamination of the endoscope before its re-use.Eighth, ensure staff members comply with published guidelines for proper hand washing and hand hygiene. Wearing gloves and other barriers, such as a mask and gown, to prevent exposure of staff members to potentially infectious agents during endoscope reprocessing also is recommended. Artificial fingernails can become colonized with bacteria and, therefore, wearing them (or extenders) when handling endoscopes may result in the recontamination of these instruments.Ninth, clean and disinfect environmental surfaces, including sinks, as recommended using an Environmental Protection Agency–registered, hospital-grade cleaner/disinfectant. Remove faucet (tap) aerators, or clean and disinfect them once a month, or more often, as required to prevent the development of biofilms. Gastrointestinal (GI) endoscopy departments may sample their flexible endoscopes microbiologically, either after reprocessing or prolonged storage, as part of a comprehensive quality assurance program.1World Gastroenterology Organization. WGO-OMGE and OMEDPractice guideline: endoscope disinfection.http://www.omed.org/downloads/pdf/guidelines/wgo_omed_endoscope_disinfection.pdfGoogle Scholar Although a controversial practice that generally is not recommended, except possibly during an outbreak investigation, the periodic monitoring of a GI endoscope may be performed to evaluate the effectiveness of an endoscope-reprocessing procedure, or to determine the cause of an identified infection. Although the lack of surveillance cultures to grow bacteria does not confirm the sterility of the endoscope, bacterial growth in any one of these collected samples likely indicates endoscope contamination and, therefore, the potential for disease transmission. Microbiological sampling of a GI endoscope can yield insightful data, but the shortcomings of this practice are significant and its applications and usefulness are limited. For example, the techniques used to collect microorganisms from an endoscope's internal channels and other sampled surfaces have not been standardized and their methodologies not validated, which can cause the results of surveillance cultures to be unreliable and inaccurate. In accordance with its standard operating procedures, a GI endoscopy department in the southwest United States each month microbiologically samples for bacterial contamination one of its several models of reprocessed GI endoscopes. On one occasion in the winter of 2009, some of the cultures collected from the sampled surfaces of a stored (and randomly selected) colonoscope, known as the test colonoscope, yielded positive growth for both patient-borne and environmental bacteria—a finding that raised the specter of disease transmission. In response, this GI endoscopy department initiated an investigation to evaluate the risk of infection during GI endoscopy and assess whether this finding might harbinger a true or pseudo-infection or outbreak. This investigation included an inspection of this GI department's endoscope-reprocessing practices. Although causally associating disease transmission with a specific GI endoscope and reprocessing breach can for a number of reasons be challenging, if rare, the medical records of patients nonetheless were examined during this investigation to evaluate whether any infections might be attributable to an improperly reprocessed GI endoscope. These records were reviewed, for example, to determine whether a patient with no other risk factors for infection and known previously not to have been infected with the hepatitis C virus had tested positive for this virus' antibodies after undergoing colonoscopy in this GI endoscopy department.2Bronowicki J.P. Venard V. Botté C. et al.Patient-to-patient transmission of hepatitis C virus during colonoscopy.N Engl J Med. 1997; 337 ([Erratum appears in: N Engl J Med 2001;344:392.]): 237-240Crossref PubMed Scopus (401) Google Scholar Because surveillance cultures collected from a colonoscope the previous month yielded no growth, only those patients on whom a GI endoscope was used during the past 4 weeks (during which time a new staff member was hired to reprocess endoscopes) were considered to be at an increased risk of infection. Although the potential for any of this GI endoscopy department's upper and lower GI endoscopes to be contaminated after reprocessing was not ruled out, this investigation focused on the reprocessing of its colonoscopes. MethodsThe suction channel, suction valve, insertion tube's exterior surface, and water-jet (or auxiliary water) channel of the test colonoscope were sampled in accordance with published microbiological techniques and this GI endoscopy department's standard operating procedures.3Standard test method for determination of effectiveness of cleaning processes for reusable medical instruments using a microbiologic method (simulated use test). ASTM International, West Conshohocken, PA2008https://doi.org/10.1520/E2314-03R08Crossref Google Scholar The genus and, when possible, both species and strain of each of the cultured bacteria were determined, to evaluate their epidemiology, mode of transmission, pathogenicity and reservoir, or source. The same surfaces of a second randomly selected colonoscope, known as the positive control because it had just been used during a procedure but had not yet been reprocessed (and, therefore, would be expected to be contaminated), were similarly sampled using these same microbiological techniques and procedures. Providing a reference for contamination, a positive control shows the specific types of bacteria that may contaminate the colonoscope during a routine procedure. It also confirms that the sampling techniques effectively recovered microorganisms from the endoscope's surfaces. If samples collected from this positive control were to yield no growth, however, then understanding that the colon's natural flora (or, indigenous microbiota) contain bacteria, this nil result would show, for example, that the sampling techniques are faulty, or, among other possible errors, that the culture media might have expired and no longer support bacterial growth invalidating the results.The same respective surfaces of a third randomly selected colonoscope used by this GI endoscopy department, known as the negative control because it had been sterilized using ethylene oxide gas before this study and, therefore, as its name suggests, should yield no growth, were similarly sampled using these same microbiological techniques and procedures. A negative control shows, in part, whether the sampling, assay, and microbiological techniques, and the handling of the endoscopes by staff, are aseptic as required. If samples collected from the negative control yield growth, then, similarly, one or more of the microbiological techniques and procedures are faulty (eg, the collected samples were contaminated during handling in the microbiology laboratory or, alternatively, the sterilization process could be ineffective), a finding that also would invalidate the results. The samples collected from these 3 colonoscopes were assayed exclusively for bacteria, not viruses, because bacteria are easy to culture and their growth is often a reliable indicator of, in addition to an endoscope-reprocessing breach, contamination of the endoscope with other microorganisms, too, including viruses (and fungi).4Queensland HealthEndoscope reprocessing Module 6.4: microbiological testing.http://www.health.qld.gov.au/EndoscopeReprocessing/module_6/6_4.aspGoogle ScholarSeveral environmental surfaces, including the tap water and a sink's faucet aerator, both of which are used by this GI endoscopy department to rinse the colonoscope after high-level disinfection, which is performed manually, also were sampled microbiologically, as were the hands and fingernails of staff members, including a recently hired staff member who, along with others, handled the 3 colonoscopes sampled and studied during this investigation. The determination not only of a potentially infectious bacterium's specific genus and species (and strain), but also source (or potential reservoir) is important to identify the infection-control breach and to prescribe effective measures to prevent disease transmission.5Muscarella L.F. Evaluation of the risk of transmission of bacterial biofilms and Clostridium difficile during gastrointestinal endoscopy.Gastroenterol Nurs. 2010; 33: 28-35Crossref PubMed Scopus (11) Google Scholar (Not performed during this investigation, which is fictional, was an inspection of this GI endoscopy department's quality-assurance documentation. Such an audit is recommended, however, and should be conducted periodically to determine, for example, whether available for training and teaching are model-specific standard operating procedures instructing staff members how to reprocess each of the several models of GI endoscopes in inventory properly.) The suction channel, suction valve, insertion tube's exterior surface, and water-jet (or auxiliary water) channel of the test colonoscope were sampled in accordance with published microbiological techniques and this GI endoscopy department's standard operating procedures.3Standard test method for determination of effectiveness of cleaning processes for reusable medical instruments using a microbiologic method (simulated use test). ASTM International, West Conshohocken, PA2008https://doi.org/10.1520/E2314-03R08Crossref Google Scholar The genus and, when possible, both species and strain of each of the cultured bacteria were determined, to evaluate their epidemiology, mode of transmission, pathogenicity and reservoir, or source. The same surfaces of a second randomly selected colonoscope, known as the positive control because it had just been used during a procedure but had not yet been reprocessed (and, therefore, would be expected to be contaminated), were similarly sampled using these same microbiological techniques and procedures. Providing a reference for contamination, a positive control shows the specific types of bacteria that may contaminate the colonoscope during a routine procedure. It also confirms that the sampling techniques effectively recovered microorganisms from the endoscope's surfaces. If samples collected from this positive control were to yield no growth, however, then understanding that the colon's natural flora (or, indigenous microbiota) contain bacteria, this nil result would show, for example, that the sampling techniques are faulty, or, among other possible errors, that the culture media might have expired and no longer support bacterial growth invalidating the results. The same respective surfaces of a third randomly selected colonoscope used by this GI endoscopy department, known as the negative control because it had been sterilized using ethylene oxide gas before this study and, therefore, as its name suggests, should yield no growth, were similarly sampled using these same microbiological techniques and procedures. A negative control shows, in part, whether the sampling, assay, and microbiological techniques, and the handling of the endoscopes by staff, are aseptic as required. If samples collected from the negative control yield growth, then, similarly, one or more of the microbiological techniques and procedures are faulty (eg, the collected samples were contaminated during handling in the microbiology laboratory or, alternatively, the sterilization process could be ineffective), a finding that also would invalidate the results. The samples collected from these 3 colonoscopes were assayed exclusively for bacteria, not viruses, because bacteria are easy to culture and their growth is often a reliable indicator of, in addition to an endoscope-reprocessing breach, contamination of the endoscope with other microorganisms, too, including viruses (and fungi).4Queensland HealthEndoscope reprocessing Module 6.4: microbiological testing.http://www.health.qld.gov.au/EndoscopeReprocessing/module_6/6_4.aspGoogle Scholar Several environmental surfaces, including the tap water and a sink's faucet aerator, both of which are used by this GI endoscopy department to rinse the colonoscope after high-level disinfection, which is performed manually, also were sampled microbiologically, as were the hands and fingernails of staff members, including a recently hired staff member who, along with others, handled the 3 colonoscopes sampled and studied during this investigation. The determination not only of a potentially infectious bacterium's specific genus and species (and strain), but also source (or potential reservoir) is important to identify the infection-control breach and to prescribe effective measures to prevent disease transmission.5Muscarella L.F. Evaluation of the risk of transmission of bacterial biofilms and Clostridium difficile during gastrointestinal endoscopy.Gastroenterol Nurs. 2010; 33: 28-35Crossref PubMed Scopus (11) Google Scholar (Not performed during this investigation, which is fictional, was an inspection of this GI endoscopy department's quality-assurance documentation. Such an audit is recommended, however, and should be conducted periodically to determine, for example, whether available for training and teaching are model-specific standard operating procedures instructing staff members how to reprocess each of the several models of GI endoscopes in inventory properly.) ResultsThe bacteria sampled from the test colonoscope and from the positive control are displayed in Table 1 and Supplementary Table 1, respectively. The insertion tube's exterior of both the negative control and the test colonoscope yielded Staphylococcus aureus (this result in not displayed in the Tables), the same strain of which also was cultured from the fingernails of the newly hired staff member. Samples from the sink's faucet aerator and tap water yielded Pseudomonas aeruginosa, Mycobacterium avium-intracellulare (MAI), and Klebsiella pneumonia; these same strains were also cultured from the test colonoscope (Table 1). None of these 3 bacteria was sampled from the positive control (Supplementary Table 1). No other environmental surfaces yielded growth of any of these 3 types of bacteria or of this specific strain of S aureus. Further, this investigation found that for the past month, although required by manufacturers' instructions, this GI endoscopy department had not been performing any of the following requisite practices: (1) routinely monitoring the concentration of the re-used high-level disinfectant; (2) leak testing the GI endoscope after each procedure; and (3) reprocessing the colonoscope's suction valve and water-jet channel after each procedure.Table 1Bacteria Sampled From the Test Colonoscope, Examples of Common Sources of These Bacteria, the Sampled Surfaces Found to Be Contaminated, and the Likely Reprocessing Breach Responsible for the ContaminationBacteriumExamples of common sourcesSampled surfaces from the endoscope and environment found to be contaminatedLikely reprocessing breach responsible for the contamination of the colonoscope with bacteriaS aureusSkin, handsMoist environments: countertops, surfacesExterior of colonoscope's insertion tubeFingernails of staff memberImproper handling of the endoscope after reprocessingImproper hand washing, hand hygieneP aeruginosaSkin, handsMoist environments: water, sinks, faucet aeratorsColonoscope's water-jet channelTap water, sink's faucet aeratorRinsing the reprocessed endoscope with contaminated waterInadequate drying of the endoscopeK pneumoniaSkin, handsMoist environments: water, sinksLower GI tract (normal flora)Exterior of colonoscope's insertion tube, suction channelTap water, sink's faucet aeratorRinsing the reprocessed endoscope with contaminated waterInadequate drying of the endoscopeMAIMoist environments: water, sinksColonoscope's suction valveTap water, sink's faucet aeratorRinsing the reprocessed endoscope with contaminated waterInadequate drying of the endoscopeE faecalisLower GI tract (normal flora)Exterior of colonoscope's insertion tubeColonoscope's water-jet channelImproper cleaning and high-level disinfection of the endoscope Open table in a new tab The bacteria sampled from the test colonoscope and from the positive control are displayed in Table 1 and Supplementary Table 1, respectively. The insertion tube's exterior of both the negative control and the test colonoscope yielded Staphylococcus aureus (this result in not displayed in the Tables), the same strain of which also was cultured from the fingernails of the newly hired staff member. Samples from the sink's faucet aerator and tap water yielded Pseudomonas aeruginosa, Mycobacterium avium-intracellulare (MAI), and Klebsiella pneumonia; these same strains were also cultured from the test colonoscope (Table 1). None of these 3 bacteria was sampled from the positive control (Supplementary Table 1). No other environmental surfaces yielded growth of any of these 3 types of bacteria or of this specific strain of S aureus. Further, this investigation found that for the past month, although required by manufacturers' instructions, this GI endoscopy department had not been performing any of the following requisite practices: (1) routinely monitoring the concentration of the re-used high-level disinfectant; (2) leak testing the GI endoscope after each procedure; and (3) reprocessing the colonoscope's suction valve and water-jet channel after each procedure. DiscussionThis GI department's active surveillance program detected the contamination of a colonoscope, which initiated an investigation that identified several significant breaches in infection control. The sampling from both the test colonoscope and the positive control of Enterococcus faecalis (Table 1 and Supplementary Table 1)—this bacterium, similar to E coli and Bacteroides species, may be found in the colon's normal flora, and therefore the sampling of any from the positive control would not be an unexpected finding—suggests improper cleaning and high-level disinfection of the (test) colonoscope. Indicating an increased risk of patient-to-patient disease transmission during GI endoscopy, this result is consistent with the observation during this investigation that staff members failed to perform several endoscope-reprocessing practices properly, including to reprocess the colonoscope's suction valve and water-jet channel after each procedure as published guidelines (and this GI endoscopy department's standard operating procedures) require. Several reports have causally associated these significant endoscope-reprocessing breaches with the transmission of infectious agents, including the hepatitis C virus and the hepatitis B virus.3Standard test method for determination of effectiveness of cleaning processes for reusable medical instruments using a microbiologic method (simulated use test). ASTM International, West Conshohocken, PA2008https://doi.org/10.1520/E2314-03R08Crossref Google ScholarThe sampling of P aeruginosa, MAI, and K pneumonia, each of which may be found on moist environmental surfaces, from the test colonoscope (Table 1) and from the sink's faucet aerator and tap water, but not from either the positive or negative control, suggests that, in addition to inadequate terminal drying of the colonoscope's surfaces and channels, the tap water used to rinse the colonoscope after high-level disinfection was likely contaminated with these 3 bacteria. That the original source of the P aeruginosa and K pneumonia may have been the GI tract of a patient, but then subsequently colonized the sink's faucet aerator resulting in contamination of the tap water and the colonoscope during water rinsing, although an unlikely scenario, cannot be ruled out. MAI, however, is an atypical mycobacterium that is not transmitted from patient to patient, and its sampling from the sink's faucet aerator and tap water indicates either environmental site as its source. Further, the sampling from the test colonoscope of the identical strain of S aureus as from the fingernails of a newly hired staff member and the negative control suggests this staff member's fingernails (and hands) as this bacterium's source and the improper handling and recontamination of the colonoscope after reprocessing the specific infection-control breach. This GI department's active surveillance program detected the contamination of a colonoscope, which initiated an investigation that identified several significant breaches in infection control. The sampling from both the test colonoscope and the positive control of Enterococcus faecalis (Table 1 and Supplementary Table 1)—this bacterium, similar to E coli and Bacteroides species, may be found in the colon's normal flora, and therefore the sampling of any from the positive control would not be an unexpected finding—suggests improper cleaning and high-level disinfection of the (test) colonoscope. Indicating an increased risk of patient-to-patient disease transmission during GI endoscopy, this result is consistent with the observation during this investigation that staff members failed to perform several endoscope-reprocessing practices properly, including to reprocess the colonoscope's suction valve and water-jet channel after each procedure as published guidelines (and this GI endoscopy department's standard operating procedures) require. Several reports have causally associated these significant endoscope-reprocessing breaches with the transmission of infectious agents, including the hepatitis C virus and the hepatitis B virus.3Standard test method for determination of effectiveness of cleaning processes for reusable medical instruments using a microbiologic method (simulated use test). ASTM International, West Conshohocken, PA2008https://doi.org/10.1520/E2314-03R08Crossref Google Scholar The sampling of P aeruginosa, MAI, and K pneumonia, each of which may be found on moist environmental surfaces, from the test colonoscope (Table 1) and from the sink's faucet aerator and tap water, but not from either the positive or negative control, suggests that, in addition to inadequate terminal drying of the colonoscope's surfaces and channels, the tap water used to rinse the colonoscope after high-level disinfection was likely contaminated with these 3 bacteria. That the original source of the P aeruginosa and K pneumonia may have been the GI tract of a patient, but then subsequently colonized the sink's faucet aerator resulting in contamination of the tap water and the colonoscope during water rinsing, although an unlikely scenario, cannot be ruled out. MAI, however, is an atypical mycobacterium that is not transmitted from patient to patient, and its sampling from the sink's faucet aerator and tap water indicates either environmental site as its source. Further, the sampling from the test colonoscope of the identical strain of S aureus as from the fingernails of a newly hired staff member and the negative control suggests this staff member's fingernails (and hands) as this bacterium's source and the improper handling and recontamination of the colonoscope after reprocessing the specific infection-control breach. RecommendationsBased on the findings of this investigation, the following recommendations are provided to prevent disease transmission during GI endoscopy.First, properly clean and high-level disinfect the colonoscope (and other GI endoscopes) including the water-jet channel and both its suction and air/water valves, even if this channel and valves are not used during the procedure. Refer to published guidelines and the operator's manual of the endoscope's manufacturer for step-by-step reprocessing instructions.Second, leak test the GI endoscope after each patient procedure in accordance with the endoscope manufacturer's instructions, to ensure the endoscope's integrity and to prevent disease transmission. Perform this test before cleaning and brushing the endoscope's surfaces and channels using a detergent solution. Visually inspect the endoscope before additional reprocessing, to ensure none of its surfaces is torn or otherwise damaged. Ensure that the endoscope is serviced properly and maintained as recommended by its manufacturer.Third, after chemical immersion, thoroughly rinse all of the endoscope's surfaces and internal channels with bacteria-free or sterile water. (The use of fresh tap water for rinsing has not been shown to pose an increased risk of infection, provided the GI endoscope is dried as described in the next recommendation.)Fourth, dry the endoscope and its internal channels, both between patient procedures and before storage, using 70% alcohol and forced air, whether the rinse water is bacteria-free, extensively treated, sterile, or from a tap.Fifth, properly store the dried endoscope, hanging it vertically in a clean and well-ventilated (dry) storage cabinet or area, with the endoscope's valves and biopsy inlet cap removed. Monitor the number of days the GI endoscope remains in storage. Although corroborating data are scant, some studies suggest that a GI endoscope may be stored for as many as 7 days before requiring reprocessing before its re-use. The reprocessing of a side-viewing duodenoscope used during endoscopic retrograde cholangiopancreatography (and bronchoscope) is recommended before each use.Sixth, monitor the concentration of the re-used high-level disinfectant at least once a day, or more often, in accordance with the manufacturer's instructions, using an appropriately labeled chemical test strip (or other technology). Note that the labeling of most high-level disinfectants requires that its concentration be monitored before each re-use to ensure the effectiveness of its active ingredient.Seventh, handle the reprocessed endoscope with care to prevent damage. Wear (new and disposable) clean or sterile gloves to prevent recontamination of the endoscope before its re-use.Eighth, ensure staff members comply with published guidelines for proper hand washing and hand hygiene. Wearing gloves and other barriers, such as a mask and gown, to prevent exposure of staff members to potentially infectious agents during endoscope reprocessing also is recommended. Artificial fingernails can become colonized with bacteria and, therefore, wearing them (or extenders) when handling endoscopes may result in the recontamination of these instruments.Ninth, clean and disinfect environmental surfaces, including sinks, as recommended using an Environmental Protection Agency–registered, hospital-grade cleaner/disinfectant. Remove faucet (tap) aerators, or clean and disinfect them once a month, or more often, as required to prevent the development of biofilms. Based on the findings of this investigation, the following recommendations are provided to prevent disease transmission during GI endoscopy. First, properly clean and high-level disinfect the colonoscope (and other GI endoscopes) including the water-jet channel and both its suction and air/water valves, even if this channel and valves are not used during the procedure. Refer to published guidelines and the operator's manual of the endoscope's manufacturer for step-by-step reprocessing instructions. Second, leak test the GI endoscope after each patient procedure in accordance with the endoscope manufacturer's instructions, to ensure the endoscope's integrity and to prevent disease transmission. Perform this test before cleaning and brushing the endoscope's surfaces and channels using a detergent solution. Visually inspect the endoscope before additional reprocessing, to ensure none of its surfaces is torn or otherwise damaged. Ensure that the endoscope is serviced properly and maintained as recommended by its manufacturer. Third, after chemical immersion, thoroughly rinse all of the endoscope's surfaces and internal channels with bacteria-free or sterile water. (The use of fresh tap water for rinsing has not been shown to pose an increased risk of infection, provided the GI endoscope is dried as described in the next recommendation.) Fourth, dry the endoscope and its internal channels, both between patient procedures and before storage, using 70% alcohol and forced air, whether the rinse water is bacteria-free, extensively treated, sterile, or from a tap. Fifth, properly store the dried endoscope, hanging it vertically in a clean and well-ventilated (dry) storage cabinet or area, with the endoscope's valves and biopsy inlet cap removed. Monitor the number of days the GI endoscope remains in storage. Although corroborating data are scant, some studies suggest that a GI endoscope may be stored for as many as 7 days before requiring reprocessing before its re-use. The reprocessing of a side-viewing duodenoscope used during endoscopic retrograde cholangiopancreatography (and bronchoscope) is recommended before each use. Sixth, monitor the concentration of the re-used high-level disinfectant at least once a day, or more often, in accordance with the manufacturer's instructions, using an appropriately labeled chemical test strip (or other technology). Note that the labeling of most high-level disinfectants requires that its concentration be monitored before each re-use to ensure the effectiveness of its active ingredient. Seventh, handle the reprocessed endoscope with care to prevent damage. Wear (new and disposable) clean or sterile gloves to prevent recontamination of the endoscope before its re-use. Eighth, ensure staff members comply with published guidelines for proper hand washing and hand hygiene. Wearing gloves and other barriers, such as a mask and gown, to prevent exposure of staff members to potentially infectious agents during endoscope reprocessing also is recommended. Artificial fingernails can become colonized with bacteria and, therefore, wearing them (or extenders) when handling endoscopes may result in the recontamination of these instruments. Ninth, clean and disinfect environmental surfaces, including sinks, as recommended using an Environmental Protection Agency–registered, hospital-grade cleaner/disinfectant. Remove faucet (tap) aerators, or clean and disinfect them once a month, or more often, as required to prevent the development of biofilms. Supplementary material Download .doc (.04 MB) Help with doc files Supplementary MaterialSupplementary Table 1Bacteria Sampled From the Positive-Control Colonoscope, Common Sources of These Bacteria, the Sampled Surfaces That Were Found to be Contaminated, and Whether Contamination of the Endoscope Was an Expected FindingBacteriumExamples of common sourcesSampled surfaces from the endoscope and environment found to be contaminatedAn expected finding?Escherichia coliLower gastrointestinal tract (normal flora)Exterior of insertion tubeNot an entirely unexpected resultBacteroids speciesLower gastrointestinal tract (normal flora)Suction valve, suction channelAn expected resultEnterococcus faecalisLower gastrointestinal tract (normal flora)Water-jet channelAn expected result Open table in a new tab Download .doc (.04 MB) Help with doc files Supplementary Material