Understand how we got here — and how to move forward.


April 26, 2018

Even when 'hospitals do everything right,' many endoscopes may be contaminated, study suggests

Daily Briefing

    Reusable medical scopes deemed ready for use on patients often might contain bacteria even after going through standard cleaning and disinfection processes, according to a study recently published in the American Journal of Infection Control.

    The current state of hospital antibiotic stewardship


    For the study, researchers sought to determine the effectiveness of endoscope drying and storage methods and the association between lingering moisture and contamination. To do so, the researchers visited three unidentified hospitals to observe drying and storing practices and conduct contamination tests on reusable endoscopes deemed ready for use on patients for colonoscopies, lung procedures, kidney stone removal, and other routine operations.

    In total, the researchers examined 45 endoscopes across the three hospitals. According to Kaiser Health News, 43 were manufactured by Olympus and two were manufactured by Karl Storz.


    Overall, the researchers found 71% of the examined endoscopes tested positive for bacteria, including Stenotrophomonas maltophilia, Citrobacter freundii, and Lecanicillium lecanii/Verticillium dahliae. The researchers noted that none of the bacteria were superbugs, but some could put patients at high risk of infection.

    The researchers said one hospital adhered to the current guidelines for cleaning and disinfecting scopes, but found safety breaches at the other two. For instance, the researchers found:

    • After handling soiled scopes, hospital technicians did not consistently change their gloves before they began disinfecting the devices;
    • Employees reused towels to wipe down scopes;
    • Employees sought to save time by turning off the cleaning cycle on the automated endoscope reprocessor;
    • Scope storage cabinets were dirty; and
    • Some scopes were hung up to dry while still visibly wet, which Kaiser Health News reports is a known bacteria risk.

    When broken down by hospital, the researchers found 62% of disinfected scopes at the hospital that met current standards tested positive for bacteria, while the other two hospitals had scope-bacteria rates of 85% and 92%.

    The researchers said the findings confirm previous studies that contamination issues extend beyond duodenoscopes, which KHN reports have been tied to at least 35 deaths in the United States since 2013. Based on their findings, the researchers said the design of many endoscopes might interfere with cleaning, even in cases in which proper protocols are put in place and followed. According to KHN, some endoscopes currently have long and narrow features where blood and other bodily fluids can become trapped.

    Cori Ofstead, the study's lead author and an epidemiologist in Minnesota, said, "Sadly, in the 10 years since we've been looking into the quality of endoscope reprocessing, we haven't seen improvement in the field." He added, "If anything, the situation is worse because more people are having these minimally invasive procedures and physicians are doing more complicated procedures with endoscopes that, frankly, are not even clean."

    The researchers recommended the health care industry accelerate the shift to more effective sterilization processes, such as those using gas or chemicals. However, KHN reports such a shift likely would require a significant investment by hospitals and clinics, as well as newly designed scopes.


    Experts also said the findings show the health care industry has not made enough progress in improving sterilization processes.

    Janet Haas, president of the Association for Professionals in Infection Control and Epidemiology, said, "These results are pretty scary," adding, "These are very complicated pieces of equipment, and even when hospitals do everything right we still have a risk associated with these devices. None of us have the answer right now."

    However, medical experts cautioned that patients should not cancel or postpone needed procedures, as the devices often prevent patients from undergoing more invasive surgeries, KHN reports. Haas recommended that patients "speak to their provider and think about the risks versus the benefits."

    FDA, which last month issued letters to three duodenoscopes manufacturers over their failure to follow up on contamination risks, said it is reviewing the study.

    Olympus, which manufactured the majority of the endoscopes examined in the study and was one of the three manufacturers to receive a letter from FDA, also said it is reviewing the study. Mark Miller, a spokesperson for the Tokyo-based company, said Olympus plans to "meet the milestones set forth by the FDA. … Patient safety has always been and remains our highest priority" (Terhune, Kaiser Health News, 4/23).

    Next: The bacteria on a plane—and how to avoid them

    Download this infographic to learn about both the obvious and less obvious locations where germs on planes are rampant.

    Download Now

    Have a Question?


    Ask our experts a question on any topic in health care by visiting our member portal, AskAdvisory.