In light of a recent outbreak linked to contaminated duodenoscopes, the U.S. Food and Drug Administration (FDA) is questioning manufacturers about their methods for cleaning the devices, the New York Times reports. The specialized scopes, which have been linked to several outbreaks in recent years, most recently infected seven patients with drug-resistant bacteria at Ronald Reagan UCLA Medical Center.
A duodenoscope is a long, flexible tube with a tiny camera attached at the end. It is inserted through the throat to help diagnose gastrointestinal tract disorders. According to NYT, these devices have been linked to serious infections at several other hospitals. In 2013, 39 patients at Advocate Lutheran General Hospital in Chicago were infected with carbapenem-resistant Enterobacteriaceae (CRE) after undergoing procedures with duodenoscopes. This is the same bacteria that caused recent infections in Los Angles. In January, Virginia Mason Hospital in Seattle said that from November 2012 to early 2014, 32 patients were infected with CRE through the scopes. Eleven of these patients ultimately died, but it is unknown whether the infections were to blame because they were already critically ill.
The FDA has never reviewed manufacturer data on how cleaning procedures for duodenoscopes. Dr. Stephen Ostroff, the agency’s chief scientist, says that the FDA has now asked device makers to provide evidence that their instructions are effective. “Institutions appear to have been doing the recommended procedures, and doing them extremely well,” said Dr. Ostroff, according to NYT. Even so, the devices may still not be completely sterile. 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.”
Duodenoscopes are very difficult to sterilize effectively, and there is no universally accepted protocol now that current methods are apparently faulty. William A. Rutala, an infection control specialist at University of North Carolina Hospitals, says that 10 billion individual bacteria can live in the inner tubing. This compares to about 100 bacteria on the surface of surgical forceps that have been used in the operating room.
Under current methods, 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; the problem with this is that it’s harmful to humans. “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.”