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Deadly Bacteria Transmitted by Duodenoscopes

Duodenoscopes and endoscopes used in retrograde cholangiopancreatography are causing infections with carbapenem-resistant enterobacteriaceae (CRE) and possibly other bacteria throughout the US. While medical societies and journals scramble to increase awareness of infection risks, medical centers are already taking precautions to avoid further infections.

DuodenoscopeThe US Food and Drug Administration (FDA), which regulates the scopes, published a written statement in USA TODAY on January 21 stating that it was “aware of and closely monitoring” the infection risks associated with the scopes. “Some parts of the scopes may be extremely difficult to access and clean thoroughly,” the FDA wrote, “and effective cleaning of all areas of the duodenoscope may not be possible.”

The FDA said it is working with manufacturers (Olympus, FUJIFILM, and Pentax) to assess potential design changes and determine whether new disinfection processes can ensure the scopes’ safety in their current configuration. However, they added that scopes’ ability to detect and treat potentially fatal digestive disorders outweighs their infection risks, so it is important for these devices to remain available.

According to USA TODAY, the pattern of illnesses began to emerge in 2012 at hospitals in Seattle, Pittsburgh, and Chicago. In each case, the culprit was CRE— dangerous superbugs that resists even last defense antibiotics. Up to 40% of infections are fatal. Most of the patients had undergone endoscopic retrograde cholangiopancreatography (ERCP).

The Seattle Times reported on January 21 that an outbreak of multidrug-resistant superbugs spread by contaminated endoscopes infected at least 32 patients at Virginia Mason Medical Center from 2012 through 2014. Neither the hospital nor health officials notified patients or the public. Many doctors who use the scopes and the patients have not been aware of the risks, or that steps can be taken to greatly reduce those risks.

“Most hospitals that do these procedures are not even looking for this problem, or they may not be aware, and that’s got to change,” Jeffrey Duchin, a physician who heads communicable disease control at the Seattle and King County (Washington) Public Health Department, told USA TODAY.

In his Guts and Growth blog, gastroenterologist Jay Hochman explained that the side-viewing scopes are more technically difficult to clean than other endoscopes because of their elevator mechanisms. He added that is likely that more common and easier-to-treat infections are also being transmitted, but these generally do not result in full-fledged epidemiologic investigations.

Duchin explained that when contaminated scopes transmit CRE, there is a lot of attention. But more common bugs may elicit little more than a quick prescription for antibiotics, and no investigation. “There’s a likelihood that we’re just seeing a very small subset of the universe of infections from these types of scopes,” Duchin told USA TODAY.

Public health officials and endoscopy experts who have studied the problem believe the FDA and scope manufacturers should do more to bring attention to the infection risks and publicize steps hospitals can take to reduce them.

“It’s fair to ask whether the FDA could have been doing more to regulate these devices and significantly reduce the risk of patient harm,” said Lawrence Muscarella, a biomedical engineer and independent consultant who advises hospitals on endoscope safety. “Patients have died, and the agency seems to be moving slowly”, he told USA TODAY.

Muscarella has identified at least 12 US outbreaks of CRE and related superbugs since 2012 that were linked to contaminated duodenoscopes — findings he published in the World Journal of Gastrointestinal Endoscopy last October. In the article, he discussed an outbreak of CRE in 2013 following ERCP procedures performed near Chicago that resulted in the infection of 38 patients, and provides recommendations to prevent CRE transmissions in healthcare settings.

In January 2014, after linking the CRE outbreak in Chicago to ERCP scopes, the Centers for Disease Control and Prevention issued a warning about the risks of spreading infections among patients who undergo the procedure.

Even when the devices are cleaned strictly in accordance with manufacturers’ FDA-approved guidelines, “they have a lot of intricate mechanisms and pieces that are very difficult to disinfect,” said Alex Kallen, an infectious disease physician at the CDC who helped direct the investigation. “There definitely is a risk of (disease) transmission with these scopes.”

To try to prevent further infections, Virginia Mason Medical Center has adopted new scope-cleaning protocols. It now requires that all scopes be quarantined after cleaning and tested for any residual bacteria before they can be reused.

The hospital had to purchase additional scopes and more staff for cleaning and testing, Duchin told USA TODAY. He said that the changes cost the hospital an estimated $1 million, but paid off in that no new infections have been linked to the scopes since the new procedures were put in place.

At University of Pittsburgh Medical Center and Advocate Lutheran General Hospital outside Chicago, officials began using a process called EtO gas sterilization to destroy any bacteria remaining on scopes after manual cleaning. The process requires special facilities and equipment because the gas is toxic, but the hospitals have reported seeing no infections since they began using it.

The gas sterilization and the quarantine-and-test approaches would be difficult for many hospitals to adopt — particularly those that have smaller staffs and budgets, Marcia Patrick, a member of the Association for Professionals in Infection Control and Epidemiology, told USA TODAY.

But Patrick said that there are things that hospitals can do to assess their risks for transmitting CRE and other infections through scopes. She says that hospitals should occasionally culture samples taken from scopes to assess whether their disinfection processes are working.

The FDA said it was also is looking at whether new disinfection processes might be adaptable to ensure safety of all types of reusable endoscopes, since many hospitals process different scopes in batches. Ensuring duodenoscope safety “is on the agency’s priority list for guidance documents we intend to publish in 2015,” the FDA statement said.

Muscarella worries that large numbers of cases go unreported. All patient illnesses or injuries linked to a medical device are supposed to be reported to the FDA by hospitals and manufacturers. But the FDA said in its statement that those reports can be spotty, because many infections are not linked back to their cause.

The American Society for Gastrointestinal Endoscopy has sent alerts to members about the infection risks associated with duodenoscopes, but it has not endorsed specific disinfection recommendations because the steps taken by affected hospitals have not been validated by the FDA.

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Kristine Novak

Kristine Novak

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About The Author:

Dr. Kristine Novak

Dr. Kristine Novak

Dr. Kristine Novak is a science writer and editor based in San Francisco. She has extensive experience covering gastroenterology, hepatology, immunology, oncology, clinical, and biotechnology research discoveries.

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