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How healthcare facilities can reduce the risk of patient exposure to Legionella

Legionnaires’ disease cases have gone up by 400 percent in the last 14 years. Healthcare facilities are increasingly on the hook to reduce their patients’ risk from this potentially deadly form of pneumonia. According to the Centers for Disease Control and Prevention (CDC), 9 out of 10 cases of Legionnaires’ disease are preventable.1 New standards, Centers for Medicare & Medicaid (CMS) requirements, news coverage, legal battles, and million-dollar fines are making it clear that facility executives and managers are responsible for taking adequate prevention measures. In fact, with ANSI/ASHRAE Standard 188-2015, Legionella water safety management programs are now an industry standard for large buildings, including most healthcare facilities in the United States.2

Develop a water safety management plan

CDC, Occupational Safety and Health Administration (OSHA), ASHRAE, and experts throughout the country agree that an effective water safety management plan (WSMP) is the key to reducing the risk of Legionnaires’ disease. The CDC recommends healthcare facilities have a WSMP that considers both buildings’ hot and cold water distribution systems and highlights building areas with high potential for Legionella growth and spread.2

Even in well-run systems, maintenance, renovations, and service interruptions can produce hazardous conditions that might lead to bacterial contamination or disease outbreaks. Routine testing for Legionella pneumophila is the best way to determine if your water safety management plan is consistently effective to prevent this. According to OSHA, “water sampling is critical to determining whether Legionnaires’ disease bacteria are present and at what levels.”3

Commit to regular water testing

Simply having a water safety management plan in place is not enough to reduce disease risk. Regularly testing for Legionella pneumophila, the bacteria responsible for the vast majority of Legionnaires’ disease outbreaks,4 is the only way to confirm that patients are not exposed to this virulent pathogen.

Culture testing is the “gold standard” for Legionella detection, but it has historically been the province of specialized laboratories with extensive expertise and requires 10–14 days for a confirmed result. The IDEXX Legiolert® Test is an easy culture test for Legionella pneumophila that has comparable accuracy and sensitivity to standard methods but a dramatically simpler procedure and a confirmed result in only seven days.5,6 The Legiolert Test’s shorter time to results enables healthcare facility managers to respond more quickly to protect their patients when Legionella pneumophila is found. At the same time, the ease of setting up the Legiolert Test and reading its results means that hospitals have more options for where and how often their monitoring is performed.

Routine testing for Legionella pneumophila is the best way to ensure your water safety management plan is effective and you are able to take swift action if needed. Unlike traditional spread-plate methods, which require subjective counts of colonies on petri plates, the Legiolert Test’s results are objective, making it 99% repeatable and reproducible7; you have consistent data upon which to make high stakes decisions on potential water quality issues.

Choose the right laboratory

It is important to choose a laboratory that is accredited for Legionella testing, the highest standard for quality. ANSI/ASHRAE Standard 188-2015 recommends using “a laboratory with demonstrated proficiency in the subject method, such as may be evidenced by certification by a national, regional, or local government agency or by an accredited nongovernmental organization.”8 Laboratories that perform Legionella pneumophila testing with a method that is part of their accreditation and quality system demonstrate that their testing is performed at the highest level of quality. Accreditation also affords important legal protection if testing results ever come under question. ISO 17025, NELAP (TNI), and the Environmental Microbiology Laboratory Accreditation Program (EMLAP; operated by AIHA) are nationally recognized accreditation options that include a Legionella pneumophila field of testing.

Dan Broder is a scientist and team leader for New Product Development in the R&D Division of the IDEXX Water line of business. Article reposted with permission from Healthcare Facilities Today

Learn more about the Legiolert Test and reducing Legionnaires’ disease risk.


CDC. Legionnaires’ disease. Vital Signs. www.cdc.gov/vitalsigns/pdf/2016-06-vitalsigns.pdf. Published June 7, 2016. Accessed April 11, 2018.

CDC. Developing a Water Management Program to Reduce Legionella Growth & Spread in Buildings: A Practical Guide to Implementing Industry Standards. Atlanta, GA: Centers for Disease Control and Prevention; 2015:ii.

Legionnaires’ disease: Water sampling guidelines [Section II:E]. Occupational Safety and Health Administration (OSHA) website. www.osha.gov/dts/osta/otm/legionnaires/sampling.html#Guidelines. Accessed April 11, 2018.

Legionellosis fact sheet. World Health Organization web site. www.who.int/mediacentre/factsheets/fs285/en/. Updated November 2017. Accessed April 11, 2018.

Sartory DP, Spies K, Lange B, Schneider S, Langer B. Evaluation of a most probable number method for the enumeration of Legionella pneumophila from potable and related water samples. Lett Appl Microbiol. 2017;64(4):271–275

Petrisek R, Hall J. Evaluation of a most probable number method for the enumeration of Legionella pneumophila from North American potable and nonpotable water samples. J Water Health. 2018;16(1):25–33.

Data on file at IDEXX Laboratories, Inc. Westbrook, Maine USA.

ASHRAE. Legionellosis: Risk Management for Building Water Systems. Atlanta, GA: American Society of Heating, Refrigerating and Air-Conditioning Engineers; 2015. ANSI/ASHRAE Standard 188-2015.


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