Doctor taking the temperature of a patient to see if she has a sore throat
HealthJune 11, 2019

Prevention Legionnaire’s infections in healthcare facilities

Legionnaires’ disease is a serious type of pneumonia, caused by Legionella bacteria and is commonly contracted when people breathe in small droplets of water in the air that contain Legionella. Cases of legionnaires have been known to spike in the summer months due to air temperature and the use of cooling towers for water, among other factors.

In 2017, health departments reported almost 7,500 cases of Legionnaires’ disease in the United States. 1 out of 10 people who get Legionnaries’ disease will die from the infection.1 While deadly, the disease can be treated with antibiotics —addressing and treating early is key to a successful recovery. Sentri7’s real-time alerting provides your team with information and clinical workflows to quickly address Legionnaires’ cases.

Read on to discover more about Legionnaire’s disease including mode of transmission, risk factors, symptoms, diagnostics tests, and related federal regulations.


Bacteria of the genus Legionella cause Legionnaires’ disease (LD) and Pontiac fever, collectively referred to as Legionellosis. In most cases, the disease is caused by Legionella pneumophila, particularly serogroup 1.

The bacterium is found naturally in fresh water. Water systems foster Legionella growth in many ways. Including:

  1. Building factors such as construction, biofilm and water temperature fluctuations
  2. Complexity of water systems — Legionella grows best in large, complex water systems that are not adequately maintained. Health care facilities are included in this category

Once water contains Legionella, it can be aerosolized through devices such as cooling towers, showers, hot tubs or fountains.

Legionnaires’ disease can then be acquired when people breathe in mist or aspirate water into the lungs containing Legionella.

Related Federal Regulations

Legionellosis is a nationally notifiable disease. On June 2, 2017, the CMS sent a memorandum entitled Requirement to Reduce Legionella Risk in Healthcare Facility Water Systems to Prevent Cases and Outbreaks of Legionnaires’ Disease (LD) to all State Survey Agency Directors.  In part, this mandate states that healthcare facilities must conduct a facility risk assessment to identify where Legionella and other opportunistic waterborne pathogens could grow and spread in the facility water system2.

Mode of Transmission

Legionella is transmitted via inhalation of aerosolized water containing the bacteria. Less commonly, Legionella can be transmitted via aspiration of drinking water. Legionella is not usually transmitted from person-to-person.

Risk factors for legionellosis include:

  • Age ≥ 50 years
  • Smoking (current or historical)
  • Chronic lung disease (such as COPD)
  • Immune system disorders due to disease or medication
  • Systemic malignancy
  • Underlying illness such as diabetes, renal failure, or hepatic failure
  • Recent travel with an overnight stay outside of the home, including stay in a healthcare facility
  • Exposure to hot tubs

Symptoms> include fever, myalgia, cough, and radiographic pneumonia. Indications that warrant specifically testing for Legionella include:

  • Patients with failed outpatient antibiotic therapy for community-acquired pneumonia
  • Severe pneumonia, in particular, those requiring intensive care
  • Immunocompromised patients with pneumonia
  • Travel history (patients who have traveled away from their home within 10 days before the onset of illness)
  • All patients with pneumonia in the setting of a Legionnaires’ disease outbreak3

Diagnostics Tests for LD are culture of lower respiratory secretions (sputum, bronchoalveolar lavage) on selective media and the Legionella urinary antigen test.4

The incubation period, which is 2 to 10 days after exposure, is critical to determine if an individual case or cluster is due to exposure in a health care facility. The CDC recommends using a 10-day period to define definite healthcare-associated Legionnaires’ disease5.

Real-time identification and alerting of a single positive culture or multiple cases of Legionella is highly critical in identifying any cases of health facility related onset of LD.  Through Sentri7’s Analytics platform, real-time alerts (via email or text) are generated and sent to the appropriate clinicians when legionella is identified. The infection preventionist can then easily determine the incubation period and evaluate whether or not the exposure might have occurred in his or her health care facility.  This alerting process can be established for any organism where a threshold has been met or exceeded.  For instance, if you wanted to be notified when there are 2 or more cases of Legionnaires’ disease on a specific nursing unit over a time period of your choosing, such as a week, you can set this up in the Sentri7 Analytics platform.

Learn more about Sentri7’s real-time alerting can be used to quickly identify and alert your teams of Legionnaires’ disease>  

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