Contaminated duodenoscopes at a Seattle, Wash., hospital are being blamed for sickening at least 35 patients and possibly contributing to 11 deaths, underscoring an ongoing challenge for practitioners and infection-control officials, who say procedures performed with the notoriously difficult-to-sterilize scopes help far more patients than they harm.

The outbreak of deadly carbapenem-resistant Enterobacteriaceae (CRE) occurred at Virginia Mason Medical Center between 2012 and 2014, but came to light only recently, says a report in the Seattle Times. Virginia Mason described the outbreak in a presentation at a conference of the Infectious Diseases Society of America this past fall.

Hospital and local health officials are defending their decision not to notify patients and their families about the situation, suggesting that doing so would have been counterproductive. "Are you going to create unnecessary fear in the public about something we can't do anything about?" asks Chris Baliga, MD, Virginia Mason's medical director of infection prevention. "Patients are at the same or higher risk all across the country," adds Jeffrey Duchin, MD, King County (Wash.) interim health officer. "We didn't feel like it was a new issue that warranted emergency notification."

Investigators say the infected scopes had been sterilized according to manufacturers' guidelines and it's not clear whether the infections were to blame for the 11 deaths, because all the patients were critically ill, mostly with terminal pancreatic or colon cancer.

Although duodenoscopes have been linked to previous CRE infections, including a 2013 outbreak in suburban Chicago that infected 44 patients and a 2012 outbreak that infected more than a dozen people in Pittsburgh, health officials say the value of endoscopic retrograde cholangiopancreatography (ERCP) procedures outweighs the risks. "The FDA feels that the lifesaving nature of ERCP, performed on more than 500,000 patients annually in the U.S., makes it important for these devices to remain available," says agency spokeswoman Leslie Woolridge.

Experts acknowledge that the design of duodenoscopes makes them extremely difficult to sterilize. Because the complex channels in duodenoscopes may be more difficult to disinfect completely, some infection preventionists suggest that they be sterilized instead of high-level disinfected. Centers for Disease Control officials have noted "the potential for contamination persisting following reprocessing" even when manufacturers' instructions are scrupulously followed.

Virginia Mason has gone a level beyond recommendations and now quarantines all scopes for 48 hours to make sure they're free of CRE and other dangerous microorganisms.

Meanwhile, the facilities involved in the Pittsburgh and Chicago outbreaks have had success using ethylene oxide gas sterilization in addition to manually cleaning the scopes, but Marcia Patrick, RN, MSN, CIC, a member of the education faculty with the Association for Professionals in Infection Control and Epidemiology (APIC) tells USA Today that gas sterilization and the quarantine approach would be difficult for facilities with smaller staffs and smaller budgets to implement. As an alternative, she recommends periodically taking bacterial cultures from scopes and testing them. "The cost of culturing is not that high," she says.

Jim Burger