General characteristics – fast facts
Germs find optimum conditions in medical facilities. In addition to the bacteria that are vital for us humans, there are also pathogenic ones that can be life-threatening. Let's have a look at one of the most dangerous types of bacteria for human beings: Legionella pneumophila serogroup 1 – a rod-shaped, gram-negative, unencapsulated, spore-free bacterium.
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.
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
Pontiac fever, a milder form of legionellosis, is characterized by flu-like symptoms. Legionnaires' disease, on the other hand, is a serious type of pneumonia and can have a severe course. In particular if it is not treated properly, or not treated at all.
In principle, these infections can be controlled using therapeutic measures. However, 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 as well as premature and newborn babies. These high-risk groups are particularly in need of protection.
German Drinking Water Ordinance & Legionella
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. Systems accessible to the public must be tested on an annual basis, while commercially used systems must be tested every three years. The competent health authority sets individual testing intervals for mobile supply systems.
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. In addition to chemical and thermal disinfection, UV irradiation and various operational and structural options are available in order to combat Legionella.
These systemic measures are justified when individually combined. However, the meticulous search for the causes is challenging.
Local measures
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. 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.
Find out more about Legionella and our infection prevention solutions.