Legionella is the Problem You Don’t Think You Have

Updated on April 7, 2023

In hindsight, the outbreak could have been prevented. A long list of consultants warned you that all the risk factors for Legionnaires’ disease were there. They recommended testing and said that there were easy and effective treatments available if the problem could be caught early. But as is so often the case, inertia had its way. Maybe in the moment it felt easier not to know, or maybe the task of monitoring and prevention fell to the wayside behind a long list of other seemingly more pressing matters. Now more patients are infected, and public health professionals are knocking at your door along with the press, lawyers, and loved ones who are left wondering why their family members died from a disease that could have been prevented with a handful of inexpensive water tests. 

Legionella is the problem you don’t think you have until you have it, making this story all too common. Legionellosis or Legionnaires’ disease is a type of severe pneumonia caused by Legionella bacteria, which grows in and spreads through building water systems. And even though testing indicates that up to half of American hospitals could have Legionella lurking in their water systems, the majority of acute care centers choose not to test for Legionella in their water supply, leaving the problem to fester until an outbreak occurs.

In immunocompromised populations the risk of death for healthcare-acquired Legionnaires’ disease ranges from 25-30%. The lethality of this disease is due in part to the delay in diagnosis and appropriate treatment of the disease. Legionnaires’ pneumonia doesn’t look any different from other forms of pneumonia. This disease doesn’t show up on the typical testing panels doctors order for patients suspected to have pneumonia. Instead, physicians must take the extra step to order a specialized test called the urinary antigen test. This test  identifies one of the primary disease-causing strains of Legionella. And thanks to public awareness campaigns, more doctors are testing for Legionella using this test. But even if that test is run, it only tests for one member of the Legionella family, Legionella pneumophila, serogroup 1. The problem is that there are more than 60 members (species) of the family and more than half cause disease. Culture of patient specimens is recommended to identify all known strains of Legionella but is often not ordered. Matching the strain of Legionella in the patient to the strain found in your water system gives you the epidemiological data that either rules out your facility as the source or prepares you to respond effectively. 

The sobering fact is that many cases of Legionnaires’ disease in the U.S. go undiagnosed until it is far too late for their patients, and patients who die from Legionella pneumonia may never have the cause of their illness brought to light. This is why the CDC’s estimate of the number and cost of Legionella cases seen each year is a serious underestimate. 

Early diagnosis is critical because Legionella is responsible for a particularly severe form of pneumonia, landing most patients in the ICU. And while there are highly effective antibiotic treatments available, the first-choice antibiotics for pneumonia like penicillin are ineffective. Many physicians are first alerted to the possibility of legionellosis when their first-choice antibiotics don’t work. By the time a urinary test is ordered and results are back, some patients are already knocking on death’s door. 

The most effective time to detect and treat Legionella is before infections occur. Testing for Legionella in your building water system takes just 10-12 samples from faucets, showers, hot water tanks, recirculation lines and other water fixtures from across your facility. This gives you a representational snapshot of the level of colonization in your water system. Most tests cost approximately $100. These samples can be bundled with tests for other common waterborne pathogens like nontuberculous mycobacteria (NTM) and Pseudomonas which combine with Legionella to cost our healthcare system approximately 2.4 billion dollars annually. That is why I often refer to Legionella as the gateway bug to increased awareness of other waterborne pathogens.

I should note for hospital administrators thinking they can do Legionella water testing themselves,  in-house clinical labs are ill-equipped and unaware of best practices and specialized methods used for environmental testing.  It’s worth the peace of mind knowing that the tests are done right by an experienced and accredited environmental laboratory.

Aside from testing, I highly recommend healthcare administrators include certified water management specialists on the decision-making teams running and maintaining your facilities. And for those without a water management specialist at hand, the American Society of Sanitary Engineers (ASSE) has developed the first professional qualifications standard (Standard 12080) for Legionella Water Safety and Management Specialists. As an instructor for this certification training for this standard, I can say that it offers fantastic training on the subject. Finally, ASHRAE (the American Society of Heating, Refrigeration and Air-Conditioning Engineers), has published Standard 188 and Guideline 12-2020 to provide guidance for prevention and management of Legionella

These measures exist to protect your facility as well as your patients. Legionella is a highly litigated disease, and cases almost always result in headlines and speculation due to the high mortality rate and a history of major healthcare-associated outbreaks in acute and skilled nursing facilities (SNF). 

With 10% of SNFs and 30% of acute care facilities now testing for Legionella, the landscape is better than it once was. But the U.S. lags far behind other countries in terms of proactive requirements for water management and testing. While guidelines from ASHRAE, the CDC, CMS and The Joint Commission all recommend facilities perform a Legionella risk assessment and have a water safety and management plan, testing for Legionella has been left to the discretion of the facility. Six states have heeded the call with newly introduced legislation seeking to change this, and I’m hopeful that more will follow. But in the meantime, there is no reason to wait. No one should die from bacteria in your water system. The first step to ending Legionnaires’ disease is to test your water systems—potable and non-potable–before cases occur.  Test to Protect!

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Janet Stout, PhD

Dr. Janet E. Stout is an infectious disease microbiologist and executive V.P. and founder of Special Pathogens Laboratory, A Pace Laboratory. Dr. Stout is recognized worldwide for her pioneering research in Legionella. Her expertise includes detection, prevention and control strategies for Legionnaires’ disease in building water systems. Dr. Stout’s 30-year career working to end Legionnaires’ disease includes hundreds of published articles and book chapters, positions on numerous industry committees, and the development of the ASSE’s first professional qualifications standard for Legionella Water Safety and Management Personnel. She also speaks and teaches an online certification course.