At least 39 people are included in an outbreak of multidrug-resistant infections spread by contaminated medical scopes at Virginia Mason. But health officials say the hospital has successfully halted the outbreak.

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More cases of “superbug” infections tied to contaminated medical scopes have been detected at Seattle’s Virginia Mason Medical Center, along with evidence of a separate cluster of potentially dangerous bacteria in other patients, newly released public records show.

At least 39 people are now included in the outbreak of multidrug-resistant infections spread by specialized duodenoscopes, up from 32 acknowledged in January by officials at Public Health – Seattle & King County.

In addition, four people not treated with those devices were infected with a shared strain of unrelated bacteria, according to internal emails released in response to a Seattle Times disclosure request.

“It does appear that there is another E. coli strain circulating among these patients,” wrote Dr. Kristen Wendorf, an epidemiologist with the Centers for Disease Control and Prevention who is based in Seattle.

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But Dr. Jeff Duchin, interim public-health officer, said the new cases do not indicate a worsening local problem. In fact, a new gold-standard protocol for cleaning the devices started last year appears to have halted the outbreak.

“The good news is that since Virginia Mason started their new infection-control system, we haven’t seen more CRE,” Duchin said, referring to the carbapenem-resistant Enterobacteriaceae bacteria linked to the outbreak.

“It suggests it’s working.”

It’s not known whether any of the additional patients died, Duchin said. Eleven patients were confirmed to have died in the original outbreak, though the role the infections played, if any, could not be determined.

Virginia Mason officials declined to discuss the new cases or the additional cluster of infections, citing pending litigation.

At least three local residents have filed lawsuits against the hospital or Olympus America Inc., the manufacturer of hard-to-clean duodenoscopes implicated in similar outbreaks at hospitals nationwide.

The seven new cases were detected based on patient samples collected between June 2014 and November 2014, months after the original outbreak that stretched from 2012 to early 2014, the emails indicated. They included five new cases of CRE and two so-called hyper-AmpC cases, unusual strains of multidrug-resistant E. coli bacteria.

(The CRE cases reported at Virginia Mason are different from the so-called “nightmare bacteria” reported at hospitals in other cities, because although they’re drug-resistant, they don’t produce enzymes that make them more dangerous.)

In all but one of the cases, patients were treated with the devices before the start of a new protocol in which hospital staff clean the scopes as directed, then culture them to test for any bacteria that could cause disease and quarantine them until they’re free of the germs. It’s a process piloted by Virginia Mason, recommended by the CDC and now adopted by hospitals locally and across the nation.

“We view it as the best approach and probably the safest approach that you can come up with,” said Chris Lavanchy, engineering director in the health-devices group at ECRI Institute, a Pennsylvania patient-safety advocacy organization.

One case, however, occurred in a patient who had the procedure known as ERCP, or endoscopic retrograde cholangiopancreatography, after the new protocols were implemented at Virginia Mason. But the patient could have been infected elsewhere, Duchin said, having undergone that procedure and others at other hospitals.

“We maintain confidence that the cleaning, culturing and quarantine procedures in use at VM remain effective and are a current best practice for endoscope safety,” he added.

Tracking uncovers E. coli

The cluster of E. coli cases was detected in patients who’d never had ERCP at Virginia Mason, though they had had other gastrointestinal endoscopic procedures performed there, according to the emails. Duchin couldn’t say which procedures those included, or whether they may have caused the infections.

Such a cluster of shared infections could have been found in any medical center, he said, because multidrug-resistant organisms are a serious and ongoing national problem. They were detected at Virginia Mason only because officials were “going above and beyond” the efforts of other hospitals to track and control infections.

“We don’t know where they acquired them, when they acquired them or how they acquired them,” he added.

There are likely many more cases of infections tied to ERCP and other procedures than are ever detected, Duchin said.

That’s a point echoed by Dr. Marisa D’Angeli, an epidemiologist with the state Department of Health, who created a database to track the Virginia Mason cases.

“The intense scrutiny of E. coli cases at VM was done for an outbreak that has been controlled,” she wrote in an email, adding that other facilities don’t routinely conduct the same type of genetic testing. “If that was routinely performed, we really don’t know what would be found in terms of relatedness of strains.”

About 500,000 ERCP procedures are performed in the U.S. each year, using long, flexible tubes outfitted to hold tools used to diagnose and treat problems with the bile and pancreatic ducts. Those devices have been found to retain dangerous bacteria, even after cleaning according to manufacturers’ instructions.

The federal Food and Drug Administration recently warned that the devices might be impossible to clean as directed and Olympus, the manufacturer, issued new guidelines and tools to health providers. The Virginia Mason protocol exceeds those new directions.

Health officials knew about the new cases as early as Jan. 20, the day before The Seattle Times first reported on the Virginia Mason outbreak, the emails showed.

But Duchin said focusing on the total number of outbreak cases — or deaths — is statistically “not that meaningful” since the number detected roughly reflects the number the health providers were able to test.

“We don’t know the exact number anyway,” he added.

Virginia Mason officials notified all 39 patients or their families who were affected by the outbreak, Duchin said. Hospital officials declined to confirm that, citing pending litigation.

The entire episode underscores the need for vigorous infection control and constant vigilance about hospital-acquired infections, which affect about 1 in every 25 patients, according to the CDC.

“If you clean up the scopes, they’ll just move around a different way,” Duchin said.