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Duodenoscopes cause of E. coli outbreak in Washington
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Researchers have identified contaminated duodenoscopes as the cause of a multidrug-resistant Escherichia coli outbreak at a Washington state hospital in 2012-2013, despite the fact that trained staff had adhered to and even exceeded the cleaning protocols provided by the manufacturer of the reusable devices.
“Although the endoscopes had been reprocessed according to industry standards, we identified contaminated endoscopes that might have facilitated the transmission of the multidrug-resistant [MDR] organism,” Kristen Wendorf, MD, MS, of the CDC’s Epidemic Intelligence Service, said in a press release. “In the wake of the recent outbreak of CRE due to contaminated endoscopes, we suspect endoscope-associated transmission of bacteria is more common than recognized and not adequately prevented by current reprocessing guidelines.”
Kristen Wendorf
Wendorf, along with Jeffry S. Duchin, MD, of the University of Washington, and colleagues investigated the extent of the outbreak, which was initially detected by the Washington State Public Health Laboratory. Molecular testing identified a cluster of AmpC-producing E. coli isolates from seven patients between November 2012 and August 2013. These isolates shared novel genetic markers, suggesting a common source.
Thirty-two case patients ultimately were identified during the investigation, each of whom had complicated pancreatic or biliary disease and had undergone endoscopic retrograde cholangiopancreatography (ERCP) at the same hospital since 2010. Of these patients, 34% died during the investigation. Sixty-four percent of the deaths occurred during hospitalization within 30 days of the date that the E. coli isolate was obtained, the researchers wrote, although it cannot be determined with any certainty whether the infections had been the cause of the deaths. The most common diagnoses among these seven patients included pancreatic cancer, colon cancer, primary sclerosing cholangitis and renal/pancreatic transplant.
Jeffry S. Duchin
The difference in mortality rates among patients with carbapenem-resistant AmpC E. coli and non-carbapenem–resistant AmpC E. coli infections was significant (P = .004), the researchers said.
A review by the endoscope’s manufacturer found that the hospital staff had followed the guidelines for cleaning and reprocessing the devices and even exceeded the industry standard. However, seven of the eight ERCP endoscopes submitted to the manufacturer showed at least one serious defect that had gone undetected during hospital testing. Additionally, among the hospital’s 60 endoscopes, which had been cultured after reprocessing in November 2013, 7% harbored gram-negative bacteria, including two ERCP scopes that were contaminated with AmpC E. coli, despite rigorous manual cleaning by hospital staff.
The hospital has since undertaken even more stringent measures to minimize the risk of hospital-acquired enteric infections associated with the use of duodenoscopes, according to the researchers.
“Our investigation highlights the value of public health surveillance using molecular epidemiological methods in identifying outbreaks that otherwise might go undetected,” Wendorf told Infectious Disease News. “Health care providers should take extra precautions to prevent transmission of pathogens through endoscopy, including ensuring meticulous scope cleaning and disinfection, establishing an ongoing multidisciplinary (including GI, infection preventionists and hospital epidemiology) quality assurance program, and conducting routine surveillance cultures to assess adequacy of reprocessing. Health care providers also should be aware of recent CDC guidance for surveillance cultures of duodenoscopes.” – by John Schoen
Disclosure: Wendorf reports no relevant financial disclosures.
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