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Legionella Prevention 

Begin With The End In Mind

Stephen Covey probably never thought his iconic phrase, “Begin with the end in mind,” would be applied to a public health problem. The end we have in mind is the end of Legionnaires’ disease. In Covey’s book, The Seven Habits of Highly Effective People, he states that: "The extent to which you begin with the end in mind often determines whether or not you are able to create a successful enterprise."

Unfortunately, success has been elusive when it comes to preventing building-associated Legionnaires’ disease. If this effort is to be a successful enterprise, we need your help. It is possible that you are already helping. Maybe you’re raising awareness of the need to test for Legionella in buildings at risk. These buildings include those with hot water recirculation, large buildings of at least 10 stories, healthcare facilities, and buildings with devices such as cooling towers, decorative water features, or whirlpool spas/hot tubs. Or perhaps you are part of one of the many organizations now involved in Legionella prevention and control.

Before we get to prevention, let’s understand the problem. In 2015, prevention efforts began to focus on water management as a strategy to put an end to the increase in reported cases. Since 2000, there has been a steady increase in the number of reported cases (Figure 1). The most recent statistics from the Centers for Disease Control and Prevention (CDC) show that the rate of reported cases of Legionnaires’ disease in the U.S. has grown by nearly five and a half times since 2000.

It was the early 1980s when the link between infection with Legionella and exposure to building water systems was proven; sadly, it was not until 2015 that the first industry standard for the prevention of building-associated Legionnaires’ disease was published (ASHRAE Standard 188, Legionellosis: Risk Management for Building Water Systems). ASHRAE Standard 188 describes a risk management approach to prevention, focusing on managing water systems. This marked the beginning of a shifting regulatory environment. ASHRAE Standard 188 was quickly followed by public health laws in the State of New York, the publication of a Legionella toolkit by the CDC, and a memorandum issued by the Centers for Medicare and Medicaid Services (CMS). While helpful, following the instructions in these documents will not, in and of itself, end Legionnaires’ disease.

Some people remain ill-informed – possibly misinformed – or believe a simple policy document constitutes a robust water safety and management program. For example, ASHRAE Standard 188 calls for a water management program team. However, too often we see an individual acting as the water management team rather than having a multidisciplinary group serving in this role. Typically, a healthcare facility water management program team would include representatives from facilities engineering, infection prevention, administration, risk management, subject matter experts, and water treatment service providers.

The ASHRAE standard states that, “The program team shall have knowledge of the building water system design and water management as it relates to Legionellosis.” Facilities engineers and managers might have the knowledge of the building water system and its design, but not the knowledge about the links to transmission of the disease. Infection preventionists can define the high-risk patient areas included in the sampling plan and the engineers can select the locations representative of the building water system.

It is critical that knowledge inform the multitude of decisions needed to prevent Legionnaires’ disease. For example, the decision whether to test, what method to use, and how often to test remains at the discretion of the facility according to ASHRAE, CDC, and CMS. Currently, the only exception in the U.S. is New York, where testing for Legionella in cooling towers and healthcare facilities is mandated by law.

Interestingly, public health organizations like CDC approach making a strong recommendation for testing stating, “Environmental testing for Legionella is useful to validate the effectiveness of control measures.” According the CDC, factors that might make testing for Legionella more important include:
• Difficulty maintaining the building water systems within control limits.
•  A prior history of Legionnaires’ disease associated with the building water systems.
•  A healthcare facility that provides inpatient services to people who are at increased risk for Legionnaires’ disease.

CMS took two steps forward and three steps back with the reversal of the 2017 requirement for healthcare facilities to develop and implement a water management program that considers the ASHRAE industry standard and the CDC toolkit. CMS required that this program “include control measures such as physical controls, temperature management, disinfectant level control, visual inspections, and environmental testing for pathogens.” In 2018, CMS “revised” the memo to remove the requirement to test and noted (in red letters) that the decision to test was at the discretion of the facility.

What’s the problem with that? The only way to know if your water management program is effectively controlling Legionella is to test for Legionella. Full stop.

When you do make the decision to test for Legionella, be sure to use an accurate and defensible test. All manner of new tests are coming to the market. Some have undergone reasonable comparative trials against the gold standard culture test – based on the international standard ISO 11731, Water Quality — Enumeration of Legionella – and some have not. Consult with your accredited microbiology laboratory and ask about their methods:
• Do they participate in a Legionella proficiency program such as CDC ELITE or the Public Health England’s international program?
• How do they report results and identify Legionella to the species and serogroup level? Is the identification presumptive or definitive?
• Can they perform molecular methods such as quantitative Polymerase Chain reaction (qPCR) for reporting results within 48 hours?

Protect yourself. Don’t leave the selection of test method or test laboratory to a vendor. Why? They won’t be questioned about the accuracy of the method and expertise of the laboratory they recommended … you will.

Here is a Legionella déjà vu
The past

It’s 1995 and the first paper detailing the many ways construction activities, especially in hospitals, can increase the risk for hospital-acquired Legionnaires’ disease is published. These include pressure changes and re-pressurization, pile driving, and prolonged stagnation (low use/no use). The authors recommend “surveillance cultures of potable water collected before, during, and after excavation or shutdown, and repressurization of supply water to the hospital.”
The present

At least 15 cases of Legionnaires’ disease have been diagnosed in patients of a brand new $361 million Ohio hospital, including one death. The first cases were identified in April and May 2019, within days of the grand opening. The focus of most building engineers during construction is to make deadlines and to be code compliant. Prior to occupancy, and to comply with most state plumbing codes, new construction piping is treated with chlorine per a standard method – usually AWWA C651, Disinfecting Water Mains – and a water sample is tested for E. coli and fecal coliforms. Testing for Legionella is not a code requirement.

The problem

In the interim between commissioning and occupancy, Legionella likely regrew to pre-chlorination levels. Legionella testing, if performed three weeks prior to occupancy, would alert the hospital to the potential risk to patients – especially the immunocompromised.

The solution

Look to ASHRAE Standard 188, Section 8, for information on the risks of delayed occupancy and measures to take to address this well-known risk.

You can help end Legionnaires’ disease by not repeating the mistakes of the past and by becoming more knowledgeable about this deadly disease, detecting Legionella, and approaches to prevention.

• ANSI/ASHRAE Standard 188-2018, Legionellosis: Risk Management for Building Water Systems establishes minimum legionellosis risk management requirements for building water systems. ASHRAE Atlanta, GA
• CDC (Centers for Disease Control and Prevention), 2018. Toolkit: Developing a Water Management Program to Reduce Legionella Growth and Spread in Buildings. CDC, Atlanta. https://www.cdc.gov/legionella/wmp/toolkit/index.html
• Covey, S. (1989). The seven habits of highly effective people. New York: Simon and Schuster.
• Franklin County Public Health. Legionnaires’ Disease at Mt. Carmel Grove City Hospital (6/10/19). https://myfcph.org/legionella
• Mermel LA, Josephson SL, Giorgio CH, Dempsey J, Parenteau S. Association of Legionnaires’ disease with construction: contamination of potable water? Infection control and hospital epidemiology : the official journal of the Society of Hospital Epidemiologists of America 1995; 16(2): 76-81.
• Stout, JE, VL Yu, RM Vickers, et al. The ubiquitousness of Legionella pneumophila in the water supply of a hospital with endemic Legionnaires’ disease. New Engl J Med 306:466-468, 1982.
• Wright DR. (Director, Survey and Certification Group. Centers for Medicare & Medicaid Services, Center for Clinical Standards and Quality/Survey & Certification Group). 2017. Memo to State Survey Agency.