4 Virginia Mason patients dead amid bacterial outbreak. It's not clear that's what killed them

Over the past six months, 31 patients hospitalized at Virginia Mason Medical Center in downtown Seattle were infected with a bacteria that can cause pneumonia, meningitis, and wound or bloodstream infections.

Four of those patients have since died.

Klebsiella is a bacteria usually found in health care settings, and often resistant to antibiotics.

Public health officials say the outbreak at Virginia Mason is "ongoing," but that the number of new infections is decreasing.

Virginia Mason has sent letters to patients it suspects were exposed.

The patients who died already had complex diagnoses when they arrived at the hospital, so it’s unknown if it was the bacteria that killed them.

The infected patients were hospitalized in various departments, including inpatient medical beds, an intensive care unit, and an operating room.

The public health agencies investigating the outbreak haven’t yet figured out where in the hospital patients were infected or what the source of the bacteria is.

Public health officials say the ongoing risk to Virginia Mason patients is unknown because it can take months for an infection to show up as an illness.

Virginia Mason says it has implemented "increased safety measures" since identifying the outbreak, and that it has provided treatment to infected patients.

"While the risk of transmission is extremely low for patients, we continue to take proactive steps to avoid additional transmission," Sydney Bersante, interim president of Virginia Mason Medical Center, wrote in a statement. "We are continuing to investigate the source of this outbreak jointly with local and state public health partners."

There is more information about the outbreak on the hospital's community resources page.

4/26/23: This story and headline have been updated to provide additional information.