• Knowledge

    Legionella pneumophila – Danger from water

    What you should know about Legionella

    Building up knowledge about Legionella and other water-associated pathogens is essential in order to recognize risks, avoid infections and implement preventive measures in a targeted manner.

    This knowledge page provides a detailed overview of Legionella, its characteristics, transmission paths, clinical pictures and protective measures.

    Legionella are environmental germs that are widespread worldwide and occur naturally in bodies of water – including drinking water systems. Under favourable conditions, they can multiply rapidly and become a health hazard. Specifically Legionella pneumophila serogroup 1 is the most dangerous type of bacteria in this genus.

    It is a rod-shaped, gram-negative, unencapsulated, spore-free bacterium.

    legionella-film-temperatures-centered

    Natural & artificial habitat

    In low and therefore harmless concentrations, this widespread environmental bacterium occurs naturally in all bodies of water across the globe – including groundwater and drinking water. Drinking water systems provide the perfect living environment for Legionella: mainly pleasant temperatures between 25 and 45 degrees Celsius – ideal conditions for a breeding ground.

    They can only be killed at temperatures above 60 degrees Celsius. However, these survival artists are gradually developing a resistance to heat.

    Replication & biofilm

    Stagnant water, low water exchange rates, dead pipes and low water pressure are all conducive to their reproduction. All of this also promotes the formation of biofilm.

    And this is where the danger lurks. If Legionella bacteria settle into the biofilm, then their growth will increase exponentially.

    • Amoebae can serve as a host for Legionella
    • Once enclosed by it, uninhibited reproduction begins until the host cell bursts.
    • The released Legionella look for new hosts.
    • And the process starts all over again.

    In addition, biofilms protect bacteria from disinfection measures, among other things, and increase resistance to other factors in their environment.

    Transmission paths

    Transmission to humans occurs via sanitary and water installations that carry water contaminated with Legionella. Simply drinking such water or mere skin contact is considered harmless. There is only a risk of infection if waterborne pathogens reach deep into the lungs via atomized water droplets – so-called aerosols – when inhaled. This results in different patterns of disease.

    Diseases & symptoms

    Infections with Legionella can cause these diseases:

    Pontiac fever: a milder form of legionellosis, is characterized by flu-like symptoms:

    • Increased body temperature up to a fever
    • Cough
    • Headache
    • Aching limbs
    • Nausea
    • Malaise

    Legionnaires’ disease: a severe pneumonia, which can be life-threatening if left untreated, has the following symptoms, among others:

    • High fever
    • Dry cough
    • Headache
    • Muscle pain
    • Chest pain
    • Chills
    • Abdominal pain with diarrhea & vomiting
    • States of confusion

    In principle, these infections can be controlled using therapeutic measures, but they do not provide for lasting immunity.

    Lethality

    Legionella infections can also be fatal. The lethality rate of Legionnaires’ disease amounts to between 5% and 9% in travel-related and community-acquired cases. For healthcare-associated cases it even amounts to approximately 13%. The situation is different for vulnerable groups of people whose immune system is weakened. In this case the death rate can be estimated at 5 to 30 percent with appropriate case management.

    Groups of people at risk

    Particularly vulnerable people include

    • the elderly
    • seriously ill patients
    • premature and newborn babies.

    These high-risk groups are particularly in need of protection.

    Facts from Germany (Europe)

    • Special precautionary measures must minimize, or ideally eliminate, any sources of danger.

      In Germany, for example, periodic testing for Legionella has been introduced. This measure is now anchored in the German Drinking Water Ordinance.

      Examination intervals:

      • Systems accessible to the public: yearly
      • Commercially used systems: every three years
      • Mobile supply systems: individually (determined by the compdetent health authority)

      If the Legionella antigen is detected in the urine from a patient in a medical facility, then the source of the infection must be clarified and investigated. In addition, the statutory reporting obligation applies in the event of a positive finding. The case must be reported to the public health department within 24 hours of detection. This is followed by an examination of the drinking water system. If Legionella is detected, then the Legionella concentration must be evaluated.

      As soon as the technical action level of 100 colony-forming units per 100 milliliters of drinking water is reached, the obligation to provide notification and to take action comes into effect. In high-risk areas, zero colony-forming units per 100 milliliters must not be exceeded. If this occurs, then restrictions on use must be imposed immediately and further investigations must be initiated.

    • Systemic measures

      As a rule, corresponding measures must be taken when the action levels are reached. The following methods exist to combat Legionella:

      • chemical disinfection
      • thermal disinfection
      • UV irradiation
      • various operational and structural options

      These systemic measures are justified when individually combined. However, the meticulous search for the causes is challenging. Given the usually complex water supply infrastructure and the high resistance of biofilms and bacteria, the focus should preferably be placed on where the danger can be averted.

      Local measures

      The use of local protective measures actively ensures the safe use of drinking water at the point of use. i3 water filters – Point-of-Use or as inline filters – offer a safe, simple and ready-to-use solution for efficient infection prevention.

      They ensure safety for patients, medical staff and visitors – preventively, in suspected cases or in the event of positive findings. In order to save valuable time in an emergency, it is always advisable to have a certain number of filters in stock as a proactive measure.

      We have compiled this information for you in an animation worth seeing.

    legionella-film-temperatures

    Zum Abspielen des Videos musst du den Marketing Cookies zustimmen:

    Legionella and (healthcare) water hygiene – what you need to know

    Facts from the USA

    • In the United States, the Centers for Disease Control and Prevention (CDC), the General Services Administration (GSA) and the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE), among others, provide guidance, guidelines, requirements, and standards for monitoring building water systems in order to control Legionella in healthcare facilities.

      The Centers for Medicare & Medicaid Services (CMS) requires all healthcare settings to comply with ASHRAE Standard 188.

      Building a water management program (WMP) is essential to reducing the risk of Legionella growing and spreading. The ASHRAE industry standard combined with the Legionella WMP toolkit, and the Legionella control toolkit provided by the CDC are the primary resources in developing one.

      A number of additional knowledge resources are available. These are constantly updated by the authorities. To name just one more essential document: the Water Infection Control Risk Assessment (WICRA) for Healthcare Settings.

      Without getting too detailed at this point, we would like to mention some general facts:

      It is recommended that water parameters such as temperature, disinfectant residuals, and pH levels be monitored frequently. Areas where water moves slowly or even stagnant need to be identified.

      Routine testing for Legionella is recommended using traditional culture methods that report colony forming units or PCR testing.

      Confirmation and reporting of a positive Legionella diagnosis is important so that the possibility of an outbreak and the source of exposure can be investigated.

      The CDC defines an outbreak as two cases of Legionnaires’ disease and/or Pontiac fever in a 12-month period.

      Response measures are required if potable water conditions allow for Legionella growth whenever more than 1 colony-forming unit (CFU) per milliliter is detected.

      In addition to chemical disinfection and temperature control, UV irradiation and various operational and structural options are available to combat Legionella.

    legionella-film-artificial-habitat

    Zum Abspielen des Videos musst du den Marketing Cookies zustimmen:

    Legionella and water hygiene in healthcare in the U.S. – what you need to know