19 Legionella – Kaiser Permanente said 19 recent Legionella cases tied to its medical center in Santa Clara are under investigation, while the health system has already moved to add water and prevention measures as it tries to identify the source.
Kaiser Permanente is working to pinpoint what caused 19 recent Legionella infections tied to its medical center in Santa Clara, a case count that has prompted added safety steps even as most patients are recovering at home.
The health system said the illnesses were identified through “robust routine internal monitoring processes.” In a statement. Kaiser said most of those who fell sick are recovering at home. and insisted its medical center is “a safe place to visit and receive care.” Kaiser did not specify how sick the patients are. and did not say how the bacteria was detected beyond describing its monitoring.
Legionella bacteria can cause disease when they enter building water systems and people breathe in mist that contains the germs. according to the U.S.. Centers for Disease Control and Prevention.. The bacteria naturally occur in environments such as lakes and streams.. They grow best in warm temperatures between 77 and 113 degrees.. Legionella infections do not spread from person to person.
Kaiser said it has not yet determined the source.. “While we work to determine the source. out of an abundance of caution. last week we concluded additional water treatment measures and preventive measures to ensure the safety of all patients. employees. and visitors. ” the health system said.. It added that mitigation efforts mean the hospital and a medical office building “continue to operate normally.”
The infections involve Legionella, which can lead to two types of illness.. The most severe form is Legionnaires’ disease, a serious and potentially deadly pneumonia, the CDC says.. It is treatable with antibiotics, and early treatment improves recovery odds.. A milder form, called Pontiac fever, can cause aches and headaches.
The stakes can be high even when person-to-person spread does not occur. The CDC says about 1 in 10 people who get Legionnaires’ disease die due to complications from their illness. For those who contract it during a stay at a healthcare facility, about 1 of every 4 are expected to die.
The current Kaiser investigation is unfolding against a backdrop of past Legionella outbreaks where investigators traced bacteria to facility water systems and. in some cases. cooling towers or hot tubs.. Legionnaires’ disease was first discovered in 1976 after a major outbreak linked to attendees of a convention of the American Legion in Philadelphia. which resulted in 221 illnesses in Pennsylvania and 34 deaths.. Investigators eventually suspected the bacteria were airborne and were spread after contaminating the air conditioning system at the convention hotel.
Since 1976. air conditioning systems have changed. and agencies worldwide have more stringent cleaning and hygiene standards for cooling towers and large-scale air-conditioning systems. the CDC says.. The California Department of Public Health notes that Legionella can grow and spread in devices such as hot tubs. cooling towers. hot water tanks. complex plumbing systems. showerheads. sink faucets. and decorative fountains.
Routine management matters because most exposures do not lead to illness, but serious infections can occur.. Ways facility managers can reduce risk include disinfecting cooling towers and water systems. establishing a water management program. and routinely performing water system maintenance.. The CDC also says Legionnaires’ disease has been on the rise since the early 2000s.
Kaiser’s case count—19 infections linked to a single medical center—arrives at a time when local outbreaks have also led health officials to identify bacteria in specific water-related equipment.. In 2024. seven cases of Legionnaires’ were reported in the northwestern corner of the city of Westminster. and no source was ever found; the Orange County Health Care Agency said that last week.. In 2023. Contra Costa County health officials found high levels of Legionella bacteria in a Richmond day spa after two deaths. and they located two other guests with lab-confirmed Legionnaires’ disease.. Officials also said the spa’s hot tub didn’t have a permit and had never been inspected.
In 2022. health investigators uncovered the likely source of 17 Legionella infections in Napa County—people who either lived. worked. or visited downtown Napa.. Sixteen people were hospitalized. 10 needed intensive care. and one person died. according to the CDC’s Morbidity and Mortality Weekly Report.. Investigators found high levels of Legionella bacteria in a cooling tower at what was then the Embassy Suites Napa Valley on California Boulevard. and the MMWR said the cooling tower had malfunctioned. leading to very little or no injection of chemicals meant to prevent bacterial growth.. The report noted cooling towers can spread Legionella bacteria over a wide area. with people living within 0.6 miles from a tower at highest risk of infection. and said cooling towers without a comprehensive water management program or lacking routine maintenance are associated with an increased risk for Legionella colonization.
Cooling towers have also been linked to major outbreaks elsewhere. including a large outbreak in New York City last year tied to 114 cases. 90 hospitalizations. and seven deaths.. In that incident. Legionella bacteria genetically matched specimens from patients. and was found in cooling towers at Harlem Hospital and a nearby construction site. according to the city.
On ships. the CDC in 2024 reported outbreaks of Legionnaires’ disease aboard two cruise ships and identified a previously unidentified source: hot tubs located on private balconies.. The CDC said the hot tubs have become more common as new ships enter service and are subject to less stringent operating requirements than public hot tubs.. “Hot tubs can be a source of Legionella growth and transmission when they are inadequately maintained and operated. ” the CDC said.
Across these situations. the pattern is consistent: when officials have traced Legionella cases. they point to building systems that can harbor the bacteria—cooling towers in multiple outbreaks and hot tubs in other settings—while prevention steps such as water treatment. maintenance. and water management programs are emphasized.. In the Kaiser case. the same sequence appears: the infections were identified through routine monitoring. the source is still under determination. and additional water treatment and preventive measures were implemented to protect patients. employees. and visitors.
As Kaiser continues its search for the source behind the 19 infections tied to its Santa Clara medical center. the health system is trying to keep patient impact limited by acting quickly on treatment measures while work continues to determine where in the facility the bacteria may have been introduced.
Legionella Kaiser Permanente Santa Clara Legionnaires' disease water treatment public health cooling towers hot tubs
Legionella sounds like a bacteria you get from, idk, the vents? Hope they figure it out fast.
19 cases is a lot for one center. They say everyone’s recovering at home but like… were they seriously sick or just “positive tests”? Also why not say what the source is yet?
Wait so they “moved to add water and prevention measures” but didn’t say what kind of water?? Like are they switching filters or chemicals or just doing more tests? This article is kinda vague but Kaiser always says it’s safe, right.
I don’t trust hospitals when they say “safe place to visit” especially if they won’t say how sick people were. Legionella is like the kind of thing you get from dirty pools, so maybe the water feature/spa thing they have? Also how does the bacteria even get into “mist” if they’re monitoring the whole time… something doesn’t add up.