What is Legionella pneumophila?
Legionella pneumophila is a Gram-negative prokaryotic bacillus that lives and proliferates in water.
In which types of water is Legionella present, and how does it proliferate?
It is present in both natural waters (rivers, lakes, wells) and artificial basins (tanks, accumulations, closed and open water circuits). Legionella survives in a wide range of temperatures (between 6 and 63°C) but proliferates and reproduces between 25 and 42°C.
Is Legionella dangerous for human health?
Yes. The bacterium is responsible for mild pulmonary infections (Pontiac fever) or severe ones (Legionellosis) which can be fatal in elderly or immunocompromised individuals.
How is Legionella transmitted?
Infection occurs exclusively through inhalation of contaminated aerosol. There are no known cases of infection through immersion or ingestion of infected water.
How is Legionella transmitted from an infected person to a new host?
It is not transmitted from patient to patient in any way.
How can Legionella be combated?
It is combated with specific chemical procedures and treatments of the waters present in the systems where aerosol develops.
Are there regulations that identify limits and activities to control Legionella?
The Guidelines for the prevention and control of legionellosis (May 7, 2015) address the matter comprehensively and identify the thresholds and applicable procedures. Some regions have issued supplementary documents on the approach and control methods. Since February 2023, the new Legislative Decree 18/2023 has included the monitoring of Legionella pneumophila in the new Table D, officially mandating its control.
Which systems are most at risk for Legionella?
All those capable of generating aerosol. If the bacterium develops in the waters of these systems, the dispersed aerosol can be inhaled, allowing it to settle in the respiratory system. Evaporative towers and showers are the first systems to be monitored.
How to combat Legionella in evaporative towers?
Evaporative towers provide ideal conditions: temperature, light, organic food, encrustations. If the bacterium is present, the wind can carry the aerosol for hundreds of meters, posing a risk of infection to surrounding areas and buildings. The Guidelines require an anti-scaling/anti-corrosion treatments to prevent the formation of substrates favourable to its development and an adequate continuous biocidal treatment.
How to combat Legionella in showers?
The bacterium generally develops in hot water. Therefore, it is necessary to implement a continuous sanitising treatment of the sanitary circuit with systems that detect and maintain a constant active residue.
Can I use any biocide to combat Legionella?
No. The European BPR Regulation 528/2012 authorizes the use of only registered and approved biocides. From the list provided by ECHA, the European Chemicals Agency, authorized products for PT4 applications (sanitisation/remediation of sanitary water systems), PT5 (continuous sanitising treatment of water intended for human consumption), and PT11 (sanitising treatment for cooling circuits) can be selected.
How do I know if Legionella is present in my circuits?
It is necessary to hire a specialized company or an accredited laboratory to carry out targeted sampling to ascertain its presence. The appointed party will issue a certified Analysis Report (RDA) with the detected colonies (measured in cfu/l).
How can ORANGE intervene to prevent and combat Legionella?
ORANGE has been operating specifically in the sector for over 10 years. It creates DVR (Risk Assessment Documents) for legionellosis, performs specific chemical treatments, and periodic monitoring in over 150 industrial and civil facilities, and in more than 50 Italian hospitals. Our technical staff is able to identify plant and system criticalities, propose the most appropriate intervention plan, provide certified products and automation for circuit treatment, carry out control analyses, and, if necessary, perform complete sanitisation/remediation operations of contaminated systems. All of this makes ORANGE a leader in the approach and management of Legionella in Italy today.
