For the first time, the U.S. Food and Drug Administration (FDA) is asking manufacturers to provide evidence that their methods for duodenoscopes are effective, the New York Times reports. The specialized scopes, which are used to diagnose gastrointestinal tract disorders, have been linked to several outbreaks of infections from multidrug resistant bacteria in recent years. The most recently outbreak occurred at Ronald Reagan UCLA Medical Center, where seven patients were infected with carbapenem-resistant Enterobacteriaceae (CRE) through duodenoscopes.
Duodenoscopes are long, flexible tubes with a tiny camera attached inserted through the throat. The FDA has never required manufacturers to prove that their cleaning procedures for duodenoscopes were effective. The agency is now asking for this information in light of the outbreaks, said Dr. Stephen Ostroff, the agency’s chief scientist. “Institutions appear to have been doing the recommended procedures, and doing them extremely well,” said Dr. Ostroff, according to NYT. Regardless, the scopes have still spread infections. The FDA acknowledged this in a recent safety communication.
Dr. Arjun Srinivasan, associate director for health care associated infection prevention programs at the Centers for Disease Control and Prevention, said that even when health care professionals “appear to be doing everything right, there has been transmission of CRE.”
NYT reports that contaminated duodenoscopes have spread serious multidrug resistant infections at several other hospitals. In 2013, 39 patients at Advocate Lutheran General Hospital in Chicago were infected with CRE after undergoing procedures with duodenoscopes.
Virginia Mason Hospital in Seattle said in January that from November 2012 to early 2014, 32 patients were infected with CRE through duodenoscopes; 11 patients died. Because these patients were seriously ill beforehand, it is unclear whether the infections were to blame.
It is difficult to sterilize duodenoscopes effectively given their complex design, and now that current methods have been linked to infections and there is no universally accepted protocol. William A. Rutala, an infection control specialist at University of North Carolina Hospitals, says that the inner tubing can house 10 billion bacteria, compared to about 100 bacteria on the surface of surgical forceps that have been used in the operating room.
Currently, the procedure is that the scopes are cleaned with tiny brushes and then cleaned with a machine that flushes inner parts with a disinfecting chemical. The FDA is considering the use of ethylene oxide gas to clean with the duodenoscopes, although it can be harmful. “This agent itself could potentially be quite toxic, not only if not thoroughly aired afterward but in the longer term to people doing the cleaning,” said Dr. Ostroff. Another option to is to sample the devices for microbiological cultures periodically. Virginia Mason Hospital has taken this approach by testing for pathogens after cleaning according to manufacturer’s instructions and then quarantine them for 48 hours until they are safe. Dr. Andrew Ross, the hospital’s chief of gastroenterology said “Just following the manufacturer’s guidelines was inadequate,”