Seattle’s Swedish Medical Center and 20 other hospitals tested dozens of specialized medical scopes every day for a month — and found bacteria remained even after rigorous cleaning.
Medical scopes used at 21 Providence Health & Services hospitals in Washington and four other states remained contaminated with bacteria even after cleaning — the same problem that has led to possibly deadly infections in Seattle and across the U.S.
No infections were detected and no patients were harmed during the four-month trial last year, hospital officials said. But the systemwide survey confirmed their worst suspicions, according to Dr. Jack Brandabur, a gastroenterologist at Swedish Medical Center, part of the Providence system.
“We were expecting to find the same thing that others had reported, that despite adherence to strict guidelines, despite all that, bacteria can at times remain on these scopes,” said Brandabur, who led the study published recently in the journal Gastrointestinal Endoscopy.
Staff at 21 Providence hospitals tested 106 duodenoscopes and linear echoendoscopes for 30 days each by cleaning them according to manufacturers’ directions, then culturing them to see if they grew bacteria.
Microbial contamination was detected in 5 percent of more than 4,000 individual specimens collected after cleaning. Of those, 0.6 percent were bacteria that can pose a risk to human health.
The study is one of “very few systematic evaluations” of germs that linger on cleaned scopes, said Dr. Alex Kallen, a medical epidemiologist and outbreak response coordinator with the Centers for Disease Control and Prevention (CDC). No national estimates exist.
“The issue of persistent contamination remains an important one,” Kallen said in an email.
Although the Providence contamination numbers appear low, they’re confounding to the crew that oversees the extensive, multistep cleaning process aimed at the scopes used to diagnose and treat problems of the gastrointestinal tract.
“For us, we feel we’ve taken every precaution and then some,” said Shannan Hove, the registered nurse in charge of the Swedish endoscopy unit. “Nobody knew there was a problem until the problem was there.”