Scope outbreak raises troubling questions
By Gary Evans, Executive Editor of Hospital Infection Control & Prevention, published by AHC Media
An upper endoscopy procedure performed on some half million patients annually in the United States might pose risk for transmission of the emerging New Delhi variety of carbapenem-resistant Enterobacteriaceae (CRE), even if current cleaning and high level disinfection protocols are followed.
That's one of the sobering considerations in the aftermath of a hospital CRE outbreak in Illinois that did not end until the facility went beyond standard practice recommendations to gas sterilization with ethylene oxide for scopes used in endoscopic retrograde cholangiopancreatography (ERCP), according to a report from the Centers for Disease Control and Prevention (CDC).1 (For more on that switch, see story, p. 29.)
"Gas sterilization would be rare for [ERCP]," says Bret Petersen, MD, FASGE, a member of the governing board of the American Society for Gastrointestinal Endoscopy. "We use gas sterilization predominately when doing a procedure in an operating room setting where a surgeon is inserting a scope through a hole in the abdomen. But when you are working through the mouth, that would be rare and relatively impractical. This is an unusual [CDC] report. It begs a lot of questions, but also raises a lot of concerns."
The mystery is that no breaks in cleaning and high-level disinfection protocols were found. As the investigation continues, the CDC recommends that healthcare facilities continue to specifically follow the device manufacturer's reprocessing protocols for ERCP scopes. "Right now the CDC is not recommending to move from high-level disinfection to sterilization," says Alexander Kallen, MD, MPH, a medical epidemiologist and outbreak response coordinator in the CDC Division of Healthcare Quality Promotion. "Our main recommendation is that facilities review their practices to make sure they adhere to exactly what the manufacturer recommends."
The number of ERCP procedures done annually is dwarfed by those done for colonoscopy and other common endoscopies, but some 450,000 to 500,000 ERCPs are performed each year in the United States, Petersen says. The infection rate for ERCP is typically 1% or less, he adds.
The Illinois CRE outbreak is also notable for the infecting agent: a strain of Escherichia coli that is highly resistant to antibiotics due to the presence of the New Delhi metallo-b-lactamase (NDM) enzyme. CRE that produce Klebsiella pneumoniae carbapenemase (KPC) have been responsible for much of the increase of CRE in the United States, but infections of the NDM variety appear to be increasing after originally emerging in Asia.
The outbreak begins
The Illinois outbreak included nine patients with positive cultures for NDM-producing E. coli (eight clinical cultures and one rectal surveillance culture) who were identified in northeastern Illinois from March to July 2013, the CDC reported.
One of those first nine cases was in a long-term care facility. The eight other cases were treated at the same hospital, which has been confirmed to be Advocate Lutheran General Hospital in Park Ridge, IL.
Lauren Epstein, MD, a CDC EIS officer who investigated the outbreak, says, "Our leading hypothesis is that the scope became contaminated at some point and the contamination persisted on the endoscope and was transferred from patient to patient."
The hospital contacted 91 additional patients who had undergone ERCP and warned them that they had been potentially exposed to a contaminated endoscope. Of the 50 who returned, 23 (46%) were positive for NDM-producing E. coli. The hospital subsequently decided to expand patient notification to all 243 patients who had exposure to any ERCP endoscope beginning Jan. 1, 2013.
The question of CRE introduction and patient travel history is intriguing in the Illinois outbreak. NDM was first reported in 2009 in a patient who had been hospitalized in New Delhi, India, and travel history and particularly medical care in Asia might be epidemiologically important in investigating NDM outbreaks. In the Illinois outbreak, three of the CRE patients had a travel history to one of the endemic regions for NDM, but they were identified later in the outbreak, and none appeared to be the index case that introduced the pathogen, CDC investigators said.
Healthcare facilities with CRE outbreaks should consider the possibility of ERCP-related transmission, the CDC emphasizes. If ERCP-related transmission of CRE is suspected, reprocessing and preventative maintenance procedures for ERCP endoscopes should be evaluated in consultation with the manufacturer, the agency recommends. For its part, Lutheran General is staying with the gas sterilization protocol for now.
REFERENCES
- Centers for Disease Control and Prevention. Notes from the Field: New Delhi Metallo-β-LactamaseProducing Escherichia coli Associated with Endoscopic Retrograde Cholangiopancreatography — Illinois, 2013. MMWR 2014; 62(51):1051-1051
RESOURCE
- The Centers for Disease Control and Prevention has created an infection control toolkit on carbapenem-resistant Enterobacteriaceae (CRE). Web: http://1.usa.gov/1as2SZB.
