The University of Washington Medical Center-Montlake is working with local health officials and the CDC to investigate the source of infection after two patients were diagnosed with Legionnaires' disease.
Water testing at the hospital in Seattle's Montlake neighborhood has so far been negative for Legionella bacteria. The patients were treated in September and one has since been discharged, the hospital said in a Nov. 3 news release.
"We don't know the source of the patients' infections in these cases, and we may never know because often patients have very complex medical situations," said Claire Brostrom-Smith, an healthcare-associated infections manager at the public health department in Seattle and King County. "However, we consider any patient with Legionnaires' disease who stayed in a healthcare facility for part of the 14 days before symptom onset as a possible healthcare-associated infection," she said, adding that the department is working closely with the medical center on the investigation.
Two patients died from Legionella infections at the hospital in 2016. The bacteria was later detected in several heater-cooler units, equipment used to heat and cool patients during heart surgery. It was also detected in an ice machine and two sinks in the hospital's Cascade Tower.
Legionnaires' is a serious type of pneumonia that people can develop when they breathe in small droplets of water or accidentally aspirate when drinking water containing the bacteria. People 50 and older, those with lung disease or weakened immune systems are most at risk.