A University of Washington Medical Center (UWMC) patient has been diagnosed with highly probable healthcare associated Legionnaires’ disease caused by infection with Legionella bacteria, according to Public Health – Seattle & King County.

Legionella pneumophila bacteria/CDC
Legionella pneumophila bacteria/CDC

The patient was admitted to the Seattle Cancer Care Alliance hospital located at UWMC and is believed to be an isolated case. The patient’s medical history suggests that exposure to Legionella happened while hospitalized in the Cascade Tower at UWMC.

She is still hospitalized, in satisfactory condition and responding well to treatment.

UW Medical Center and SCCA have notified patients and families who are currently on the unit where the infection was discovered.  Extensive environmental testing is underway to identify a possible source for this exposure. Preliminary results from these tests will be available in approximately one week and final results in about two weeks.

Other steps being taken include:

  • The two rooms where this patient received care have been taken out of service pending culture results from water sources in the rooms.
  • The ice machine from the unit where the patient was located has been replaced.
  • All patient respiratory specimens are being tested for Legionella bacteria.
  • Patients with pneumonia are being tested for Legionella.


This is the first case of suspected healthcare associated Legionella pneumonia to occur within UW Medical Center or the SCCA Hospital since two cases occurred in August 2017. In response, UW Medical Center installed special filters on all showers and sinks in the inpatient rooms in the Cascade Tower. A robust water management plan was also developed that includes testing and monitoring of water temperature, chlorine levels and presence of Legionella. All known facility-based risk factors that may have contributed to prior cases were mitigated. The effectiveness of the filters has been validated by testing.