Q & A about Public Health’s investigation of an endoscope associated outbreak

Voluntary reporting by Virginia Mason Medical Center led to identification of an outbreak of multidrug resistant bacterial infections in 2013. After months of investigative work, Public Health—working with Virginia Mason Medical Center, Washington State Department of Health and the Centers for Disease Control Prevention (CDC)—linked the outbreak to a procedure called endoscopic retrograde cholanCREgiopancreatography (ERCP). Since discovering the risk from this procedure, our Communicable Disease Epidemiology staff has taken a leadership role in drawing national attention to this issue in the medical community. Dr. Jeff Duchin, Interim Health Officer and Chief of Communicable Disease Epidemiology answered questions about this outbreak.

What is an ERCP used for?

The ERCP procedure uses a scope, or tube, that goes through a patient’s mouth and throat to reach their upper small bowel and bile duct system. ERCP is used in persons with serious medical problems including cancers and other diseases that cause obstruction or narrowing of the bile ducts.

What kind of bacteria caused the infections?

Infections were caused by two closely-related types of bacteria that are resistant to many antibiotics. In some cases, the bacteria were also resistant to powerful antibiotics called carbapenems.  These bacteria are referred to as CRE (carbapenem resistant Enterobacteriaceae).

Was the outbreak caused by a CRE “superbug?”

No. The type of CRE that has caused outbreaks in other healthcare facilities has been referred to as a “CRE superbug.” It usually produces an enzyme that inactivates carbapenem antibiotics. The outbreak we investigated was not caused by this type of CRE, which did not have a carbapenemase enzyme.

What is the role of Public Health in this investigation?

The main role of Public Health – Seattle & King County in responding to the ERCP-associated outbreak  was to 1) investigate the outbreak, 2) identify the source of the problem, and 3) stop the risk to patients.

Did any patients become sick?

Yes, thirty-two patients became sick from bacterial infections related to ERCP. They were diagnosed and treated appropriately by Virginia Mason.

Did any patients die?

Eleven patients infected by the bacteria died. However, the patients all were receiving medical care for other serious underlying illnesses—mainly terminal colon or pancreatic cancer–and it is not known what role, if any, infection may have played in most of the cases.

Why weren’t patients notified that their endoscope procedure put them at risk of infection?

Without specific medical actions to recommend, no ongoing risk, inability to accurately determine which patients might have been exposed to incompletely cleaned scopes, and potential harm from notification, our communicable disease staff and CDC officials did not require Virginia Mason to notify individual patients. The final decision whether to notify patients was left to the Virginia Mason team.

What were the considerations in determining if patient notification was required?

Given the seriousness of the infections, we carefully considered and discussed the pros and cons of notification with CDC and the Virginia Mason team. These considerations included:

1) Is there a need for specific medical action for the patients who may have been exposed to a contaminated endoscope? (For example, is there a need for treatment or testing of exposed patients?)

Unfortunately, the health consequences of infection with the type of bacteria associated with the outbreak are unclear and as this outbreak unfolded, we would not have been able to tell patients what the health implications were for exposure to an ERCP procedure before the problem was fully identified and corrected.

There were also no specific medical actions to recommend to persons who may have had a procedure with a contaminated endoscope—there is no testing that can determine whether they have been infected and no treatment possible if they don’t have symptoms. People who are exposed to this bacteria don’t necessarily get sick. For asymptomatic patients, the bacteria is dormant, so it is difficult to even tell if they have been infected and there’s no action they can take.

2) Is there ongoing risk to the patient or the public that can be reduced?

We determined that appropriate safeguards had been taken to prevent future risk. Once the problem was recognized, effective measures were taken to address the problem of transmission of infection by endoscopes promptly. The hospital began culture testing of the scopes after they were cleaned and not using them until the test was negative, as well as enhancing already adequate cleaning and disinfection procedures and infection control precautions. Testing and holding all ERCP scopes until the cultures were negative was a safety measure that was well beyond the standard recommended practice and what virtually all other hospitals were doing.

3) Are there potential harms of notification?

In discussions with the CDC, we identified potential harms of notification. Thousands of people received endoscope procedures over the years at just this one facility, but incomplete cleaning of the endoscopes only happens in some cases. Because we could not identify precisely which patients were exposed to incompletely cleaned scopes, many more patients would need to be notified than were actually at risk. Notification of an exposure without clear health implications and with no recommended actions to take could reasonably be expected to result in potential harms such as fear, emotional distress and the potential for negative unintended consequences (i.e., to interfere with willingness to have needed ERCP procedures for serious medical conditions) in the absence of clear benefits, particularly for unexposed and uninfected persons.

Patients undergoing similar procedures at other hospitals across the country were likely also at risk because the same type of scopes and reprocessing procedures are used nationwide but would not be notified.  The problem of cleaning and disinfecting these types of scopes was not new information, similar situations were previously reported.

What has Public Health done to inform the public about the risk from endoscope procedures?

It’s very important to inform the public, the medical community and regulatory agencies about the issue of potentially inadequate endoscope reprocessing standards and risk for transmission of infection. We felt that the best way to do that was through presenting the information at public meetings, through working with CDC to engage the Food and Drug Administration and the endoscope manufacturers, and through publishing our finding in a peer review publications (submitted). We presented our investigation at a meeting of the Infectious Diseases Society of America in October 2014 (however because of the Ebola outbreak it did not get media attention at the time) and at a local meeting of infectious disease physicians.  Presentations are also scheduled for other medical meetings by physicians at Virginia Mason.

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I am a risk communications specialist at Public Health - Seattle & King County.