July 21, 2015 — A bronchoscope has been linked to 14 patients who tested “positive” for CRE and pan-susceptible Pseudomonas aeruginosa, according to a regulatory report filed with the FDA seven months ago, on December 24, 2014.

This case may document the first time the FDA was notified of a bronchoscope’s possible transmission of CRE. Infections caused by these superbugs are generally difficult to treat and may be associated with a mortality rate of as high as 50%.

The regulatory report states that the bronchoscope had remained contaminated with the bacteria, which also included carbapenem-resistant Klebsiella pneumoniae (CRE), after reprocessing.[*]

The report also acknowledges that the “exact cause” of the incident “could not be conclusively determined at this time,” although it states that the implicated bronchoscope had been repaired by a third-party vendor. The device was removed from service to prevent additional infections.

The risk of duodenoscopes infecting patients with CRE or a related superbug is now well-recognized.

As the FDA has discussed in several recent safety communications, multiple outbreaks of carbapenem-resistant Enterobacteriaceae have been linked to duodenoscopes since 2012, with associated morbidity and mortality.

The first of these FDA alerts was published in February, and it concluded that the design of duodenoscopes may impede effective cleaning. “Although the complex design of duodenoscopes improves the efficiency and effectiveness of ERCP,” the FDA wrote in this alert, “it causes challenges for cleaning and high-level disinfection. Some parts of the scopes may be extremely difficult to access and effective cleaning of all areas of the duodenoscope may not be possible.”

Pulmonologists use bronchoscopes to diagnose and treat a variety of lung- and airway-related diseases in patients, whereas gastrointestinal physicians use duodenoscopes to examine and treat diseases of the pancreatic and bile ducts.

Update (Oct. 2015):  The FDA may have appreciated this article’s focus on bronchoscopes. Two months after the publication of this article in July 2015 — which informed the public, for the first time, that bronchoscopes, like duodenoscopes, also appear prone to remaining persistently contaminated and transmitting potentially deadly ‘superbug’ outbreaks — the FDA published a safety communication on September 17, 2015, entitled: “Infections Associated with Reprocessed Flexible Bronchoscopes: FDA Safety Communication.”


While not well publicized, bronchoscopes are also prone to transmitting CRE and related multidrug-resistant bacteria, and this risk may be underestimated.

To date, U.S. health officials have not publicly advised the public about this risk. However, a U.S. hospital’s implementation of certain corrective measures may be important to prevent the transmission of CRE during bronchoscopy, too, not just during ERCP.

Bronchoscopes are used about 500,000 times a year in the U.S. Similarly, duodenoscopes are used about 670,000 times last year in the U.S. to perform ERCP, or endoscopic retrograde cholangiopancreatography.

Carbapenems are “big gun” antibiotics that are the “last defense” against serious hospital infections.

Quality and Safety Services and Case Reviews for Hospitals, Manufacturers, Patients: The CDC’s recent safety alert stresses that a healthcare professional “with expertise in device reprocessing” should immediately assess a healthcare facility’s reprocessing procedures. Click here to read about Dr. Muscarella’s quality and safety services and comply with this safety alert.”

Few other details known about this outbreak

Few other details are known about the cluster discussed in this Dec. regulatory report. Yet, this case suggests that flexible endoscopes, like bronchoscopes, less complex in physical design than duodenoscopes can also pose a risk of transmitting CRE.

On February 19, 2015, the FDA published an alert — the first of several communications by the agency discussing duodenoscope safety — acknowledging that “the complex design of ERCP endoscopes (also called duodenoscopes) may impede effective reprocessing.” The FDA also noted inauspiciously in the alert that “[m]eticulously cleaning duodenoscopes prior to high-level disinfection should reduce the risk of transmitting infection, but may not entirely eliminate it.”

Patients who test “positive” for bacteria are either infected or colonized with the organism, showing no symptoms of disease.

Possible contributing factors

Factors that can contribute to a bronchoscope transmitting CRE or related multidrug-resistant bacteria are several, and include inadequate servicing and repair of the device, and use of a “leak test” during the bronchoscope’s cleaning that may not always be sufficiently sensitive to detect all types damage to the bronchoscope.

Damaged or not properly maintained bronchoscopes can harbor and retain infectious bacteria, and transmit the bacteria including CRE to patients (see: Ramsey et al., 2002 and Wendorf et al., 2015).

This 2014 regulatory report states that the bronchoscopes were serviced by a third-party, not the original equipment manufacturer. Whether the endoscope was serviced as recommended by the manufacturer, using only certified materials of known quality and durability, is unclear.

Another medical device report describing a bacterial outbreak

On August 28, 2014, a manufacturer notified the FDA that 22 patients tested “positive” for E. coli and Pseudomonas aeruginosa following bronchoscopy. Whether either of these bacteria were multidrug-resistant is unclear.

Each of this outbreak’s patients was examined using the same bronchoscope, whose o-ring was cultured and confirmed to be contaminated with these bacteria, according to the regulatory report.

Contamination of the o-rings of other endoscope models has been implicated as a risk factor for disease transmission.

This August regulatory report states that the medical facility stored bronchoscopes using (non-sterile) peel-pack covers to protect their distal tip. However, the manufacturer recommends instead that the endoscope be stored with its distal tip hanging freely, not covered, to ensure proper drying.

Other ‘superbug’ outbreaks linked to contaminated bronchoscopes

Zweigner et al. (2014) reported an outbreak in 2013 of CRE (i.e., carbapenem-resistant Klebsiella pneumonia) in an intensive care unit of a German hospital. Cultures taken from the working channel of two bronchoscopes revealed their contamination with CRE.

The outbreak ended after both bronchoscopes were removed from service and returned to the manufacturer, who observed defects in the internal surfaces of both bronchoscopes’ working channel.

As the FDA has found with duodenoscopes, Zweiger et al. (2014) reported that the infections of CRE occurred despite staff members reprocessing the bronchoscopes as recommended by its manufacturer (or by national guidelines).

Even more than a decade ago, Sorin et al. (2001) reported that 18 patients were infected or colonized with imipenem-resistant P. aeruginosa (IRPA) following bronchoscopy.

Imipenem is a carbapenem antibiotic, and whereas this multidrug-resistant bacterium (IRPA) is of the Pseudomonadaceae family and therefore not CRE, it is a related type of superbug that, like CRE, is resistant to carbapenems and can be deadly.

These findings suggest, like the December 2014 regulatory report, that contaminated bronchoscopes — not just duodenoscopes — may pose a risk of transmission of CRE and other deadly multidrug-resistant gram-negative bacteria.

Further, in his peer-reviewed article, “Risk of Transmission of Superbugs during Gastrointestinal Endoscopy,” I wrote that:

“A demonstrated public health threat both in the United States and globally, transmissions of CRE are not exclusive to GI (gastrointestinal) endoscopy. Other types of flexible endoscopic procedures, including bronchoscopy and cystoscopy (as well as other types of medical procedures unrelated to flexible endoscopy), are also identified risk factors for infections (and predictors for colonizations) with CRE and related superbugs.”

Urological instrumentation, too

Additionally, like both duodenoscopes and bronchoscopes, reusable urological equipment has also been linked to superbug outbreaks.

Koo et al. (2012) report an outbreak of CRE (i.e. NDM-1 Klebsiella pneumoniae) linked to the contaminated video camera head of urological instrumentation.

Chang et al. (2013) similarly report an outbreak of ertapenem-resistant Enterobacter cloacae (a type of superbug) at a hospital in Taiwan. These researchers determined that a contaminated ureteroscope was responsible for this outbreak.


The following recommendations are provided to healthcare facilities to prevent superbug outbreaks during bronchoscopy. This list is not complete:

1. Duodenoscopes featuring a complex design (i.e., a forceps elevator mechanism) are not the only types of flexible endoscopes that have been linked to CRE infections.

  • Reports also associate bronchoscopes (and urological instrumentation) with outbreaks of CRE.

2.  Establish a comprehensive quality assurance and safety program for the thorough cleaning and disinfection or sterilization), known as reprocessing, of all types of flexible endoscopes.

  • Ensure reprocessing staff are properly trained and know how to reprocess each flexible endoscope in inventory.
  • Perform periodic inspections of staffers’ reprocessing practices to ensure compliance with manufacturers’ instructions and reprocessing competency.

3.  Meticulously follow the manufacturer’s instructions for reprocessing bronchoscopes and other types of flexible endoscopes. Review the recommendations provided in the nationally recognized “multi-society” consensus guideline, which was published in 2011.

  • If using an automated endoscope reprocessor, or AER, resolve any conflicts between the reprocessing instructions provided by the AER and endoscope manufacturers.

4.  Perform leak testing as recommended by the endoscope’s manufacturer, although enhanced leak testing may, at times, be required.

5.  Ask the manufacturer for a maintenance schedule for servicing the endoscope.

  • CRE transmission following endoscopy may be considered whenever an outbreak of CRE is identified (Zweiger et al., 2014).
  • If not properly maintained and serviced, flexible endoscopes can reportedly transmit multidrug-resistant bacteria despite being reprocessed as recommended by the manufacturer (Zweiger et al., 2014).

6. Thoroughly dry the endoscope after reprocessing both between patient procedures and before the endoscope’s storage, to prevent infection.

Also, consider reviewing Dr. Muscarella’s peer-reviewed article, “Risk of Transmission of Superbugs during Gastrointestinal Endoscopy.”

[*] Footnotes: (i) The association between a device and infections by no means assures the device was solely responsible for and necessarily transmitted the infections. More data would be required to conclude such a likely causal relationship between the two. (ii) Regulatory reports submitted to the FDA routinely describe important clinical cases and experiences, but the findings and conclusions of these reports generally have not been peer-reviewed and may be incomplete, or, at least in part, inaccurate.]


In the context of this article “related superbugs” are multidrug-resistant bacteria that are related to, but are not, CRE, per se. Specifically, they are gram-negative bacteria that are either:

(1) resistant to carbapenem antibiotics, although not of the Enterobacteriaceae family (and therefore not CRE; NDM-1 carbapenemase-producing Acinetobacter baumannii is an example); or

(2) are a multidrug-resistant member of the Enterobacteriaceae family, although currently remain susceptible to carbapenem antibiotics (e.g., extended spectrum beta lactamase-producing Klebsiella pneumoniae).


Chang CL, et al. Outbreak of ertapenem-resistant Enterobacter cloacae urinary tract infections due to a contaminated ureteroscope. J Hosp Infect 2013;85:118-124.

Koo VS, et al.  Multidrug-resistant NDM-1 Klebsiella outbreak and infection control in endoscopic urology. BJU Int 2012;110:E922-E926.

Muscarella LF. Contribution of tap water and environmental surfaces to nosocomial transmission of antibiotic-resistant Pseudomonas aeruginosa. Infect Control Hosp Epidemiol 2004;25:342-345.

Olson J. HCMC alerts patients: Medical instrument wasn’t fully sterilized. Twin Cities.com [updated 2010 June 22; cited 2014 August 20]. Available from: URL: http://www.twin-cities.com/minneapolis/ci_15353711

Ramsey AH, et al. An outbreak of bronchoscopy-related Mycobacterium tuberculosis infections due to lack of bronchoscope leak testing. Chest 2002 Mar;121(3):976-81.

Sorin M, et al. Nosocomial transmission of imipenem-resistant Pseudomonas aeruginosa following bronchoscopy associated with improper connection to the Steris System 1 processor. Infect Control Hosp Epidemiol 2001;22:409-413.

Wendorf K, et al. Endoscopic Retrograde Cholangiopancreatography-Associated AmpC Escherichia coli outbreak. Infect Control Hosp Epidemiol 2015 Jun;36(6):634-42.

Zweiger J, et al. A carbapenem-resistant Klebsiella pneumoniae outbreak following bronchoscopy. Am J Infect Control 2014;42:935-40. [Letter]

Article by: Lawrence F Muscarella, PhD. Originally posted 7-21-2015. Updated: 9-30-2016, Rev A.

Copyright (2015). LFM Healthcare Solutions, LLC. All rights reserved. Dr. Muscarella is the president of LFM Healthcare Solutions, LLC, an independent quality improvement company. Click here for a discussion of his quality improvement healthcare services.

E: Larry@LFM-HCS.com. Twitter: @MuskiePhD

One thought on “A Bronchoscope Was Linked to a ‘Superbug’ Outbreak in 2014”
  1. Still under reported, still voluntary notice to FDA and still blaming third parties, designed to switch liability risk. Not much changes with Olympus does it?

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