Dr. Muscarella’s following perspectives provide additional insights into The Seattle Times’ article:

‘Superbug’ outbreak sparks changes at region’s hospitals (March 8, 2015)

Enhanced surveillance

This article in The Seattle Times reports that a “superbug” outbreak at Virginia Mason, linked to a specialized type of gastrointestinal (GI) endoscope contaminated with nightmarish bacteria, has pushed other hospitals, in Seattle and other U.S. cities, to enhance their surveillance and safety procedures.

Click here to read a related article that provides additional details about this superbug outbreak at Virginia Mason that infected 32 people, including 11 who died (although it’s unclear whether the superbug was responsible).

This newly published Times article further reports that no similar types of superbug outbreaks linked to GI endoscopes have been detected at Swedish Medical Center, in Seattle.

According to the Times, Swedish Medical Center recently began sampling these specialized GI endoscopes daily for bacterial contamination.

Also now performing these tests on the endoscope, according to the Times, are Harborview Medical Center, the University of Washington Medical Center, Providence Everett and the Veterans Affairs Puget Sound Health Care System.

These surveillance tests are designed to determine whether bacteria, especially multidrug-resistant ones, could be retained by the GI endoscope, even after recommended cleaning, and transmitted from one patient to another, potentially causing dangerous infections.

Quality Reviews for Patients, Hospitals, Manufacturers:  Click here to read about Dr. Muscarella’s expertise and legal assessments of the causes of healthcare-associated infections, including “superbug” outbreaks linked to contaminated GI endoscopes and other reusable medical equipment.

Number of ERCPs performed in Seattle

These specialized GI endoscopes, which are called side-viewing duodenoscopes, are used to perform ERCP, or endoscopic retrograde cholangiopancreatography.

According to the Times, “Swedish performs about 1,000 ERCP procedures a year, placing it second in local volume only to Virginia Mason, which logs about 1,800 procedures annually. UW Medical Center performs about 500 ERCPs each year, Providence Everett performs about 250 and Harborview about 200. VA Puget Sound performed 89 procedures in Seattle in 2014.”

Limitations of the “test-and-hold” policy

The surveillance testing of the GI endoscopes is a featured step of a practice now being called “test-and-hold.”

This practice is only one component of an even larger set of activities by the Centers for Disease Control and Prevention (CDC) called “Detect and Protect,” which also feature more aggressive infection prevention and antibiotic stewardship.

After the ERCP endoscope is cleaned and disinfected, it is tested, or sampled microbiologically, and then “quarantined” — that is, removed from service for two days until hospital officials can assess whether the GI endoscope is likely free of dangerous bacteria.

The ECRI Institute recently published its advice about microbiologically sampling GI endoscopes.

Art or science?

Sometimes overlooked, however, such sampling practices can be more of an “art” than a “science” lacking standardization and varying as much on the culture medium used to grow the bacteria as on the staffer who is sampling the endoscope.

That is in large part why, to date, the CDC has not published a validated testing protocol for sampling GI endoscopes and other complex medical devices. Too many variables that are difficult to control can affect the results.

A primary concern discussed by this blog’s author – Lawrence F Muscarella, PhD – is this sampling method’s proneness for yielding a “false negative” result.

That is, this test can yield a (false) result indicating that the GI endoscope is “sterile” (i.e. no bacterial growth two days after testing and incubation) when, in fact, the instrument’s crevices and crannies were contaminated with unrecoverable deadly superbugs.

Because of the testing method’s inherent shortcomings, hospitals may not always collect or capture these bacteria when employing this test-and-hold policy adopted by Virgina Mason among others.

Just like the inability of hospitals at times to remove superbug bacteria from the endoscope’s contaminated surfaces during cleaning and brushing, this sampling test cannot guarantee the retrieval of organisms from these same contaminated surfaces (although only one “colony-forming-unit” of the bacteria is needed to demonstrate that the endoscope is contaminated).

And the result could be a hospital’s unwitting use of a contaminated GI endoscope thought (erroneously) to be safe, resulting in superbug transmissions and deadly infections.

The journal “Endoscopy”

Dr. Muscarella’s concerns with the potentially significant limitations associated with the microbiological sampling of  flexible endoscopes were expressed in 2010 in an editorial published in the peer-reviewed medical journal “Endoscopy.”

“The study of Auerman et al. [3] also demonstrates the significant limitations of microbiological culturing, or surveillance sampling, of a flexible endoscope – a procedure that may be used by some medical facilities to monitor the effectiveness of their reprocessing practices [2–4, 9]. Like Fraser et al. [2], Auerman and colleagues [3] sampled a contaminated side-viewing duodenoscope but recovered no bacteria – a false-negative result that erroneously implied the endoscope’s “sterility”. Only when Auerman and colleagues, like Srinivasan et al. [15], modified their sampling technique to include brushing of the endoscope’s suction channel in addition to flushing it, was the effectiveness of sampling improved sufficiently to culture the outbreak strain of Kl. pneumoniae[2, 3]. Whereas recovery of bacteria from a sampled channel generally verifies its contamination (i. e., a true-positive result), non-recovery does not prove its sterility [2, 3]. Nevertheless, despite the possibility of invalid results, endoscope sampling may, at times, yield meaningful data [4, 5, 7, 9].”

The CDC has acknowledged these limitations of endoscope sampling, but with less apparent concern, stating (click here):

“The sensitivity of the interim protocol has not been determined. A negative culture does not completely exclude the possibility of a contaminated duodenoscope. However, positive culture results should lead to some action …”

EtO gas sterilization

Another well-publicized, proposed mitigation to prevent CRE transmissions during GI endoscopy — the use of ethylene oxide gas (EtO) sterilization, which some hospitals are now employing in lieu of the test-and-hold policy — appears, in contrast, to be all but fool-proof, despite its own set of significant limitations.

The use of EtO sterilization, however, like the test-and-hold policy which is additionally prone to false-negative results, will like require the hospital to purchase additional, expensive GI endoscopes.

For some busy GI endoscopy units, the purchase of as much as $1M of additional equipment may be required to accommodate patient demand and the endoscope’s removal from service either for for one day to perform EtO sterilization, or for two days until the test-and-hold bacterial results are obtained.

Further, a hospital’s microbiology department — which is where the test-and-hold culture samples would be collected for bacterial growth and assessment — is equipped and instructed to perform such a bacteriologic analysis, but generally on patient specimens and cultures, not on environmental cultures obtained form the surfaces of GI endoscopes and other types of medical instrumentation.

The “fix”?

The most effective “fix” to prevent additional outbreaks of CRE in the U.S. may be to use EtO sterilization in the short term whenever feasible, and in the long term to enhance the designs of ERCP endoscopes to facilitate their more effective cleaning and disinfection.

QUOTES from The Seattle Times’ article: ‘Superbug’ outbreak sparks changes at region’s hospitals (March 8, 2015)

Dr. John Pauk (Swedish Medical Center’s medical director of infection control):

  • “Luckily, so far, we haven’t (identified a superbug outbreak linked to GI endoscopes at Swedish). But I don’t think any hospital system could fairly say there isn’t a potential problem with their scopes.”
  • Endoscope sampling has “kind of been on people’s radar screens, but the scope of the problem was not totally understood.”
  • “What we need to look at is, is the high-level disinfection process working, rather than looking at CRE specifically.”

ECRI Institute

  • “The reality is, as we look at this, more and more hospitals are going to encounter this bug.”

Lawrence F Muscarella, PhD (a hospital safety expert):

  • “From a patient’s standpoint, the new surveillance in Seattle and elsewhere is good news.
  • “Before undergoing an ERCP procedure, patients should ask several specific questions. For example, you can ask the hospital: ‘Did you have any CRE or related superbug infections within the last two years? Were any linked to endoscopes? What are you doing to ensure safety?’”
  • “Before, patients never knew what questions to ask, so hospitals never had to answer.”


1. Muscarella LF. Investigation and prevention of infectious outbreaks during endoscopic retrograde cholangiopancreatography. Endoscopy 2010 Nov;42(11):957-9 — click here.

2. Fraser TG, Reiner S, Malczynski M et al. Multidrug-resistant Pseudomonas aeruginosa cholangitis after endoscope retrograde cholangio-pancreatography: Failure of routine endoscope cultures to prevent an outbreak. Infect Control Hosp Epidemiol 2004; 25: 856–859.

3. Aumeran C, Poincloux L, Souweine B et al. Multidrug-resistant Klebsiella pneumoniae outbreak after endoscopic retrograde cholangiopancreatography. Endoscopy 2010; 42: 895–899.

4. Struelens MJ, Rost F, Deplano A et al. Pseudomonas aeruginosa and Enterobacteriaceae
bacteria after biliary endoscope: an outbreak investigation using DNA macrorestriction analysis. Am J Med 1993; 95: 489–498.

5. Allen JI, O’Connor-Allen M, Olson MM et al. Pseudomonas infection of the biliary system resulting from use of a contaminated endoscope. Gastroenterology 1987; 92: 759–763.

6. ASGE Standards of Practice Committee. Infection control during GI endoscopy.
Gastrointest Endosc 2008; 67: 781–790.

7. Watts R. VIHA warns 500 patients of possible blood-borne virus infection. Victoria Times Colonist. April 23, 2010.

8. Hennepin County Medical Center. Error in manufacturer’s disinfecting instructions prompts patient notificiation. [News release] June 22, 2010.

9. Alvarado CJ, Stolz SM, Maki DG. Nosocomial infections from contaminated endoscopes: A flawed automated endoscope washer. An investigation using molecular epidemiology. Am J Med 1991; 91 (Suppl. 3B): 272S–280S.

10. Muscarella LF. The study of a contaminated colonoscope. Clin Gastroenterol Hepatol 2010; 8: 577–580

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

12. Hota S, Hirji Z, Stockton K et al. Outbreak of multidrug-resistant Pseudomonas aeruginosa colonization and infection secondary to imperfect intensive care unit room design. Infect Control Hosp Epidemiol 2009; 30: 25–33.

13. Welch KC, Cohen MB, Doghramji LL et al. Clinical correlation between irrigation bottle contamination and clinical outcomes in post-functional endoscopic sinus surgery patients. Am J Rhinol Allergy 2009;23: 401–404.

14. Sorin M, Segal-Maurer S, Mariano N 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.

15. Srinivasan A, Wolfenden LL, Song X et al. An outbreak of Pseudomonas aeruginosa infections associated with flexible bronchoscopes. N Engl J Med 2003; 348: 221–227.

Posted 3/16/2015, Rev A.

One thought on “A “Test-and-Hold” Surveillance Policy to Prevent ‘Superbug’ Infections Following Endoscopy”
  1. As long as facilities, FDA and manufacturers are complicit in concealing deaths and outbreaks, these manufacturers and the FDA will continue to place their heads [and ours] in acceptable ratios compared to the number of procedures. It is up to the media, YOU, others with knowledge, experience, courage and venue to expose real losses and victims, which exceed acceptable, if it is your child, parent or loved one. The remedy will never be resolved in the courts as long as providers pay off their opponents and buy out experts like Rutala. They continue stronger than before because the FDA fails to do the job they were established to do. Far too many scope procedures are done for profit, not purpose.

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