March 26, 2018 (updated May 16, 2018)  —  Advice for preventing flexible endoscopes from transmitting potentially life-threatening “superbugs” is the focus of new research, which provides a new clinical practice for reducing this infection risk.

The association between duodenoscopes and outbreaks of multidrug-resistant bacteria is now well-documented. But whether other types of flexible endoscopes might, too, pose a risk of remaining contaminated after reprocessing and transmitting superbugs is less clearly defined.

This concern was investigated, and the complete findings and recommendations of this new research are published in a white paper I wrote – click here to download a free copy. Some of the findings, however, are presented herein.

The medical literature and the FDA’s database of medical device regulatory reports were reviewed to evaluate the potential for: (a) bronchoscopes, (b) cystoscopes, (c) echoendoscopes, (d) flexible laryngoscopes, (e) gastroscopes and (f) ureteroscopes, like duodenoscopes, to transmit carbapenem-resistant Enterobacteriaceae, or CRE, and other superbugs, including multidrug-resistant Pseudomonas aeruginosa.

The research found that these types of flexible endoscopes also can pose a risk of infecting patients with carbapenem-resistant bacteria if important safety measures are not implemented and properly executed. Carbapenems are “last resort,” broad-spectrum antibiotics used to treat serious bacterial infections.

A number of superbug outbreaks were identified during this research. In some cases, bacterial contamination of the flexible endoscope persisted despite the device reportedly having been reprocessed correctly in accordance with the manufacturer’s instructions — a finding that has been reported previously with duodenoscopes.

Remember to click here to download a free copy of a white paper I wrote that provides the complete findings and recommendations of this new research. Some of my research’s findings, however, are presented below.

An under-recognized, emergent infection risk?

Public alerts and notices focusing on the potential for these other types of flexible endoscopes to transmit superbug infections — and how to mitigate this risk — are few, however.

The paucity of such publications suggests that this risk could be under-recognized, although perhaps a serious and emergent risk.

A number of risk factors for superbug transmissions associated with these other types of flexible endoscopes were identified during this new reaearch, including the device’s complex design, its improper servicing, and wear and/or damage to the device’s internal channels.

Quality, Safety and Case Reviews, Research Performed: Click here to read about Dr. Muscarella’s quality and safety services designed to help clients reduce the risk of healthcare-associated infections, including superbug outbreaks linked to contaminated duodenoscopes and other types of reusable medical equipment.

A new clinical practice

This new research provides insights, recommendations and guidance to reduce the risk of these other types of flexible endoscopes from transmitting potentially untreatable multidrug-resistant bacterial infections.

Click here to download a free copy of my sponsored white paper, which provides all of my research’s findings and recommendations, in their entirety.

Among other advice, my research suggests that hospitals consider a new clinical practice for reducing the risk of these flexible endoscopes from infecting patients with superbugs:

  • When deemed appropriate, feasible and warranted by clinical circumstances, consider adopting and applying to flexible endoscopes — namely, bronchoscopes, cystoscopes, echoendoscopes, flexible laryngoscopes, gastroscopes and ureteroscopes — at least one of the four supplemental measures the FDA previously published in an August 4, 2015 safety communication to mitigate the risk specifically of duodenoscopes infecting patients with multidrug-resistant bacteria including CRE.
    • A hospital may conclude that sterilization of the flexible endoscope is indicated, in lieu of disinfection, particularly if — due to certain factors, including the device’s complex design, or the device’s instructions for use (IFUs) featuring cleaning and disinfection instructions that have not been properly validated for effectiveness and completeness, or the device was repaired, maintained and/or serviced using materials or components of a potentially poorer quality that may be prone to damage and to remaining contaminated — the endoscope remains persistently contaminated with bacteria after cleaning, disinfection and drying.

This recommendation that enhanced safety measures be considered at least for echoendoscope models that, like duodenoscopes, feature a forceps elevator mechanism has been previously published.

A duodenoscope model.
(Source: FDA)

However, the more comprehensive advice that hospitals consider broadening the scope of the FDA’s safety communication and applying one or more of its four supplemental measures also to bronchoscopes, cystoscopes, flexible laryngoscopes, gastroscopes, and ureteroscopes (but only as deemed appropriate and feasible and as clinical circumstances warrant) appears not to have been previously published.

The moving parts of the elevator mechanism contain microscopic, hard-to-reach crevices. If not thoroughly cleaned and disinfected, tissue or fluid and residual bacteria from one patient may remain in device crevices of a duodenoscope, exposing subsequent patients to risk of infection,” the FDA has published.

Other related articles by Dr. Muscarella

The FDA’s four supplemental measures

The four supplemental measures the FDA published in its August 4th (2015) safety communication include the microbiological sampling and culturing of the endoscope — also called the “test-and-hold” method — to evaluate its bacterial contamination after reprocessing (and prior to reuse).

Click here to read the FDA’s safety communication, which is entitled: “Supplemental Measures to Enhance Duodenoscope Reprocessing.”

Another of the FDA’s four measures is the use of ethylene oxide (EO) gas sterilization to eradicate persistent bacterial contamination of the endoscope. In several cases, outbreaks of CRE were terminated once the hospital began using EO gas to sterilize duodenoscopes.

Source: CDC

Cleaning and high-level disinfection of the duodenoscope twice before reuse, a third measure suggested by the FDA, may be the “most immediately feasible option available to the majority of endoscopy practices,” according to some researchers.

The fourth measure is the use of a liquid chemical sterilant processing system.

These four safety measures are adjunctive processes, however, that are intended to be performed in addition to – not to replace – reprocessing of the endoscope according to its manufacturer’s instructions (and published guidelines).

Notably, stakeholders have been discussing whether Spaulding’s definition of a critical device should be modified to include flexible endoscopes, or whether flexible endoscopes, currently labeled as semi-critical devices for which high-level disinfection at a minimum is required, should be reclassified as critical devices mandating sterilization after each use.

Whether applying at least one of these four supplemental measures (which the FDA recommends to mitigate the risk of duodenoscopes transmitting superbugs) to these other types of flexible endoscopes (coupled with improved designs) would provide patients with a sufficient margin of safety for the prevention of superbug infections is unclear.

New endoscope sampling protocols: validated or not?

Last month the FDA, Centers for Disease Control and Prevention (CDC) and the American Society for Microbiology (ASM) published a guide that provides voluntary protocols for duodenoscope surveillance sampling and culturing. According to the FDA, “these protocols can be used to help monitor the quality of a facility’s endoscope reprocessing procedures. Adequate monitoring may reduce the risk of infection.”

A webinar hosted last week by the FDA and CDC detailed many of the sampling steps provided in the February guide. A copy of the slides presented during this webinar may be downloaded by clicking here.

The rationale the CDC, FDA and ASM provided for developing these sampling protocols for duodenoscopes was “to provide a standardized, validated method to health care facilities for surveillance sampling and culturing duodenoscopes,” according to one of the webinar’s slides.

But these protocols raise a number of questions, some of which were not addressed either during the webinar or in last month’s published guide.

For instance, organizers during this webinar asserted several times that this sampling protocol has been “validated.” Indeed, the protocol has been standardized, but its being validated, according to understood definitions, is questioned.

An interim sampling guidance document the CDC issued in March 2015 — and that last month’s new guide replaces — stated that: “a negative culture does not completely exclude the possibility of a contaminated duodenoscope.” In other words, that protocol was prone to incorrect, or “false-negative,” results.

Further, at least with regard to that interim duodenoscope surveillance protocol, the FDA wrote that “the false positive rate, the false negative rate and the limits of detection for microbial surveillance have not yet been established for this method.”

On its face, this same limitation inextricably associated with the March 2015 interim sampling protocol would seem to also apply to the validity of the final sampling protocols the CDC, FDA and ASM published in last month’s guide.

Seeming to downplay the usefulness and possibly problems with the validity of this protocol, the FDA and CDC’s new sampling guide states that, “(c)urrent U.S. guidelines for endoscope reprocessing and infection control do not recommend endoscope surveillance sampling and culturing.”

It is unclear why, if the protocol has been standardized and validated, the FDA and CDC would not encourage its routine use to prevent superbug infections.

The possibility that the FDA and CDC’s sampling protocols are prone to “false-negative” results and have not been independently validated was not discussed in detail during the webinar, or in the guide.

Discussing the general sampling of flexible endoscopes, some have noted that there is “the possibility of false-negative results owing to the insensitivity of the techniques to detect potential contamination.”

Interestingly, the FDA and CDC’s guide published last month acknowledges that neither agency independently validated these sampling protocols, writing in the guide instead that the “(t)hree manufacturers of duodenoscopes in the U.S. have completed benchtop testing to validate the sampling and culturing protocols (data not shown).”

No matter the limitations, however, the surveillance sampling and culturing of flexible endoscopes for some hospitals may be an important tool for the “early notice of potential problems.”

Technical Consultant: Dr. Muscarella provides expert opinions, case reviews and advice for hospitals, device manufacturers and consumers about the causes of healthcare-associated infections (“HAIs”) linked to contaminated upper and lower GI endoscopes, among other devices. Contact him (using your smart phone):  Email | Text (SMS) | Skype

FDA bronchoscope safety communication

In July 2015, I published an article entitled, Contaminated Bronchoscopes Linked in 2014 to a ‘Superbug’ Outbreak.”  

The article focused on a regulatory report filed in Dec. 2014 that had linked bronchoscopes — apparently for the first time — to a CRE outbreak. According to the report, fourteen (14) patients tested “positive” for CRE (and P. aeruginosa) after undergoing a diagnostic bronchoscopic procedure.

The regulatory report stated that the bronchoscope had repeatedly remained contaminated with CRE despite being reprocessed.

Two months after my article was published, the FDA published a safety alert on Sept. 17, 2015, entitled, “Reprocessed Flexible Bronchoscopes — Risk of Infection.” This alert provides several recommendations to mitigate the risk of infections due to a contaminated bronchoscope.

This FDA communication acknowledges that the agency had received reports the following year in 2014 of persistent contamination of reprocessed bronchoscopes despite users following the manufacturer’s cleaning and disinfection instructions.

However, this federal communication did not recommend users consider applying to bronchoscopes (and to other flexible endoscope types) at least one of the four supplemental measures the FDA had published the previous month, in August 2015, to mitigate the risk of reprocessed duodenoscopes transmitting superbugs.

Whether the FDA might update the August 2015 safety communication to include application of the four supplemental measures to bronchoscopes and other types of flexible endoscopes, too, is unclear.

Endoscope types, uses

Bronchoscopes are routinely used to examine (and monitor), diagnose and treat diseases of the airways and lungs. Curvilinear-array echoendoscopes are used to perform endoscopic ultrasound, or “EUS,” in both the upper and lower GI tracts. Cystoscopes and ureteroscopes are primarily used to examine, diagnose and treat diseases of the lower and upper urinary tract, respectively.

Moreover, flexible laryngoscopes are used to examine, diagnose and treat diseases of the larynx, nasal lumens and cavity, nasal pharynx and the upper airway anatomy; these devices may also be used for airway management and during endotracheal intubation. The author of this article herein previously evaluated the risk of infections associated with flexible laryngoscopes, and provided a formal set of step-by-step instructions for reprocessing these devices.

Duodenoscopes are used during endoscopic retrograde cholangiopancreatography, or ERCP, to examine and diagnose diseases of the liver, bile ducts, and pancreas. An adjustable forceps elevator mechanism is located at the duodenoscope’s
distal tip.

Remember to click here to download a free copy of a white paper I wrote that provides the complete findings and recommendations of this new research. Some of my research’s findings, however, are presented below.

Summary and conclusions

Published data indicate that bronchoscopes, cystoscopes, (curvilinear array) echoendoscopes, flexible laryngoscopes, gastroscopes and ureteroscopes, like duodenoscopes, can pose a risk of contamination and transmission of superbugs, including CRE and multidrug-resistant P. aeruginosa, if important safety measures are not implemented and properly executed. A practice for hospitals to consider is provided to reduce the risk of patient infections in these other endoscopic settings.

Article by: LFM Health Solutions, LLC. Lawrence F Muscarella, PhD., President Posted: March 26, 2018; updated May 15, 2018. LFM Healthcare Solutions, LLC. Copyright 2018. LFM Healthcare Solutions, LLC. All rights reserved. 

Lawrence F Muscarella PhD is the owner of LFM Healthcare Solutions, LLC, a Pennsylvania-based quality improvement and consulting company that provides safety services for hospitals, manufacturers and the publicEmail Dr. Muscarella for more details.

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