This posting by Lawrence F Muscarella, PhD, provides his response to a recent report that gastrointestinal (GI) endoscopes may remain contaminated with patient materials after cleaning, posing an increased risk of healthcare-associated infections.

Click here to learn about a program that Dr. Muscarella designed for healthcare facilities to reduce the risk of infection-control breaches and associated infections.

Note: This post contains link to several other posts by Dr. Muscarella that discuss the risk of disease transmission associated with GI endoscopy, and the review of each is suggested.

Study Finds Endoscopes Not Always Cleaned Properly

At the 2013 annual meeting of the Association for Professionals in Infection Control and Epidemiology (APIC), a presented abstract has caught the attention of many news outlets.

This abstract reported that 3 of every 20 sampled gastrointestinal (GI) endoscopes (used to examine the GI tract including colons) of five hospitals were improperly cleaned, reportedly retaining unacceptable levels of “bio dirt” that could pose an increased risk of patient infection.

Several news sources reported on this abstract, including Medical News Today, The Los Angeles Times. and the business network CNBC.

This abstract’s lead investigator states in an APIC news release that: “Three out of 20 is an unexpectedly high number of endoscopes failing a cleanliness criterion. … Clearly, we’d like no endoscopes to fail a cleanliness rating.”

Each year in the United States, between 15 million and 20 million endoscopic procedures are performed to screen patient for cancers of the GI tract.

This same news release adds: “The cleaning protocols for flexible endoscopes need improvement, such as guidelines tailored to the type of scope or identifying if there is a critical step missing in the manual cleaning process, and documented quality-control measures … These types of improvements could have a positive impact on patient safety.”

Click here to read Dr. Muscarella post: “A Legal Case and Verdict about Improperly Reprocessed GI Endoscopes.”

Healthcare facility responses

Understanding that this abstract’s findings could have significant quality-control and  public-health implications, healthcare facilities have launched constructive educational programs to address concerns patients may express about the safety of GI endoscopy and the cleanliness of its associated reusable instrumentation.

One such facility published its own press release, stating that it “conducts semiannual in-service training, in addition to annual competency checks on the staff members who wash the scopes.”

(Dr. Muscarella endorses and is associated with quality-control auditing programs. Click here fore more information.)

Professional organizations’ response

In response to this abstract presented at APIC, 2013, which is drawing national attention to the quality of endoscope reprocessing, one organization — the Society of Gastroenterology Nurses and Associates (SGNA) — recently issued the statement “What You Need to Know:  Media Coverage Regarding Bioburden Levels on  Reprocessed Endoscopes.” (Contact SGNA for more information.)

Click here to read Dr. Muscarella post: “Investigation and Prevention of Bacterial Outbreaks during Endoscopic Retrograde Cholangiopancreatography (ERCP).”

ATP Test Kits

The study on which the abstract presented at APIC, 2013, is based used a test kit intended to detect levels of adenosine triphosphate, or ATP, which reportedly is a marker for contamination from organic matter.

Briefly, this study identified the presence of ATP (adenosine triphosphate) in GI endoscopes despite the instrumentation having been “cleaned.”  (The study was funded by the 3M Infection Prevention Division, and these kits are not medical devices; their labeling has not been reviewed and cleared by the FDA.)

How accurate and reliable these ATP test kits are and what exactly these kits do, and do not, detect are therefore important questions to have answered. So too are these other questions:

What is “bio-dirt” and how well does its identification on a surface or in an endoscope’s internal channel correlate to the presence and amount of infectious bacteria or viruses?

The abstract does not specify the “nature” of the “bio dirt” that was identified in 15% of the sampled endoscopes, which raises some other related questions:

Did this “bio dirt” contain bacteria and viruses, and if so, which specific types of infectious agents were identified in 15% of these sampled endoscopes?

The biological constituents of the “bio dirt” (viruses? gram-negative bacteria? gram-positive bacteria?) identified on 15% of the sampled GI endoscopes is important to learn and to assess scientifically the associated risk of infection (e.g., a negligible, low, moderate, or high risk). If no organisms or viruses were detected in this “bio-dirt,” then the identification of this bio-dirt might not be of great concern.

According to a press release discussing this study: “The amount of ATP, in relative light units (RLUs), was measured with a hand-held luminometer. Based on previously published clinical data, a threshold for ‘pass/fail’ was set at 200 RLUs. Any instruments with more than 200 RLUs were identified as a cleaning failure.” (Dr. Muscarella cannot confirm or refute the validity of this conclusion and of these claims.)

Which specific types of infectious agents – for example, gram-negative bacteria, antibiotic-resistant gram-positive bacteria, viruses like the hepatitis C virus – do these ATP test kits reliably and consistently detect (if any of them)?


I endorse any effort to improve the quality of endoscope reprocessing and, as part of my commitment, I have developed a quality and risk-management program to contribute to this effort (<click here> for more details).

Click here to read Dr. Muscarella post: “Case Study: Faulty Disinfection of Gastrointestinal Endoscopes in Canada.”

Echoing the abstract’s claim that “the cleaning protocols for flexible endoscopes need improvement,” one healthcare facility published its own press release, stating that “health and sterilization standards need to significantly improve so that patients continue to get screened.”

But, do the cleaning protocols of GI endoscopes require improvement?  As this study suggests, might the reprocessing guidelines of professional organizations like SGNA be inadequate, “behind the curve” and “out of date”?  Are reprocessing staff members “falling short” and improperly cleaning GI and other types of flexible endoscopes without knowing it, to the detriment of public health?

To each of these question, I answer “No.” And much of the published medical literature would agree with me. According to the American Society for Gastrointestinal Endoscopy (ASGE), the risk of an infectious organism being transmitted to a patient by a GI endoscope is one in 1.8 million (although not everyone might agree; click here).

Further, previously published data indicate that no cases of disease transmission have been associated with GI endoscopes (and other types of flexible endoscopes) that have been cleaned (and high-level disinfected) in strict accordance with current published guidelines — such as SGNA’s step-by-step guideline, which can be downloaded by <clicking here>, or the “multi-society” guideline, which can be read by <clicking here>.

(Note: These are the same guidelines that the authors of the abstract presented at APIC, 2013, suggest require improvements: <click here>).

Click here to read Dr. Muscarella post: “Biofilms and the Risk of Transmission of Clostridium difficile during GI Endoscopy.”

To ensure the findings presented of this abstract (presented at APIC, 2013) are not misunderstood, it is also necessary to distinguish between whether this abstract reported that the 15% of sampled GI endoscopes were contaminated with “harmful bacteria” — as one report states — or rather with “bio-dirt,” the implications of which to quality control are obvious, but to patient-to-patient infection are less clear.

Click here to read Dr. Muscarella post “A Legal Case and Verdict about Improperly Reprocessed GI Endoscopes.”

Root cause analysis

The authors of this abstract may consider performing a detailed root cause analysis of the identified non-conformance – namely, of the factors that contributed to 15% of the sampled endoscopes (at 5 hospitals) containing “bio-dirt” after cleaning — to ensure every possible corrective action is developed and implemented.  (For more details about performing a root cause analysis, <click here>. One of Dr. Muscarella’s root causes analyses may be reviewed in Table 4 of this <published paper>.)

Do all types of ‘bio-dirt’ contain ‘harmful bacteria’?

Closing remarks: According to another report, one clinician concludes that: “It’s appalling that these hospitals didn’t take the necessary measures to properly and thoroughly wash these instruments.”

But, before: (i) healthcare facilities and their reprocessing staff members are admonished and (ii) dramatic actions are taken, such as, possibly, the revision of infection-control guidelines, based on this abstract’s finding, closer scrutiny and further review of the study’s underlying data, its sampling methodologies, and its assumptions are recommended. Clearly, many questions require answering.

Researching whether it may be that reprocessing guidelines do not require revision at all, but rather, as a different and suggested corrective action, that the designs of some GI endoscopes might be improved or optimized to enhance their cleaning is also recommended.

Indeed, it may also be that reprocessing staff members diligently reprocessed the 15% of the GI endoscopes found to be contaminated with “bio-dirt” exactly as the endoscope’s manufacturer instructed. This abstract’s findings do not address this issue, having not assessed staff members’ compliance with the step-by-step instructions of a published guideline.

Finally, it may be that these sampled GI endoscopes found to be contaminated after cleaning are a harbinger for future instances of disease transmission. It may also be that the ATP kits used by the study’s researchers are accurate and effective and that their use improves quality control and reduces the risk of infection.

Does this abstract’s finding that the 15% of sampled GI endoscopes were contaminated with “harmful bacteria” — as this one report concludes — or with some type of soil, the implications of which to patient-to-patient infections are much less clear?

But, again, before too many conclusions are drawn, some of which may be invalid, I recommend circumspection, the viewing of this abstract’s findings under a scientific light, the publication of additional studies to corroborate this abstract’s finding, and healthcare staff obtaining the answers to this Bg’s posed questions.

By: Lawrence F Muscarella, PhD, posted on 6-25-2013.

3 thoughts on “Response to a Report about GI Endoscopes Remaining Contaminated despite Cleaning”
  1. Dear Colleagues!
    The main obstacle to adequate high-level disinfection (HLD) is an inadequate design of endoscopes . HLD adequacy is defined not by washing machines, but by manual brushing of endoscope. Moreover, chain “machine-cabinet-container” itself has a risk of secondary infection of endoscope.

    Any further reprocessing as well as HLD have no effect without prior MANUAL BRUSHING. Today’s flexible scopes have not less than 12 (!) zones which require manual brushing. Among them – channels with small diameter and large length, other cavities, which are inaccessible for brush and are only flushed.

    Herewith I propose you to discuss our solution of this problem.
    Recently patents in Japan and China were granted on my
    single-channel, non-valve endoscope with disposable component (see, section 2.1). Patents are pending in the USA, Europe, Eurasia.

    However I suppose that today’s vicious system of flexible endoscopy will change only your help and legal motivation of endoscopes manufacturers.
    Multi-channel endoscopes are not allowed! – society is increasingly talking about crimes against humanity, and how can we name the acts of infecting of hundreds of thousands of people around the world?

  2. I’m a 55 Year old male. Back in 2008, I experienced weight loss. After a negative result from a bone marrow biopsy, my personal physician recommended me to the Mayo Clinic. The Medical Institution performed a battery of tests that included, but not limited to CT scan and Upper Endoscopy. I had absolutely no stomach issues, like bloating, pain, and belly fat before my visit. In fact my stomach was flat through regular jogging.

    Three months after my Mayo Clinic visit, I began to experience severe stomach pain, and bloating. Keep in mind that all tests, including stomach biopsy were negative during my Mayo Clinic visit. The immediate suspect was endoscope contamination. It is very hard to me fathom how can such a renown institution would not fully sterilized its equipments.

    I recalled the endoscopy procedure process to be like a production line with many patients waiting to be examined. I’m still suffering from stomach bugs that refuse to go away. I’m scared to death about doing another endoscopy fearing subsequent contamination.

    In addition to my original weight loss issue, I have stomach symptoms that are making my ability to regain weight very difficult. About four years ago, I was tested positive for H-pylori. One course of antibiotic has not helped me.

    I would be glad to read any suggestions, maybe from Mayo Clinic itself.

    1. Dear Mr. Rich,

      Thank you for your comments and for sharing your story. You have used this blog as I originally designed it: to interact, to ask questions, and to seek advice and support.

      The symptoms you describe – for example, abdominal bloating – can indeed be (but is not necessarily) caused by infection with Helicobacter pylori. Whether this bacterium was transmitted to you via a contaminated instrument is unclear, but its treatment with the administration of an appropriate antibiotic by a trained professional may be indicated.

      The transmission of a H. pylori (or another bacterium or virus) via a contaminated upper (or lower) GI endoscope (e.g., an EGD endoscope), has been previously documented and requires that several criteria be met. Among them, the “index” patient displaying symptoms of infection must not have been infected with the organism prior to the GI endoscopic procedure; second, a reprocessing breach (e.g., failure to properly clean or disinfect the endoscope,including its valves and each of its internal channels) had to have occurred and, ideally, was identified; and, third, there must be a “source” patient who is infected, too, with the same organism of the same genetic makeup as the organism that infected the index patient, and who shares no other risk factors with the source patient other than both having undergone GI endoscopy in the same GI endoscopy department, with the source patient’s procedure preceding, in time, the index patient’s procedure. Knowledge of another patient who visited the same department and who also was infected with H. pylori after undergoing GI endoscopy would strongly argue for yours being an instance of patient-to-patient disease transmission. More information would be necessary to confirm transmission.

      Please seek care with a professional until your symptoms are resolved. It may be that treatment with antibiotics alone, with some changes in diet, which can be necessary as we age, may resolve your symptoms without your having to undergo another upper GI endoscopic procedure. Please look into this, check back, and let me know how your care is progressing.

      Best regards, Lawrence F Muscarella, PhD

Leave a Reply

Your email address will not be published.