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Legionella pneumophila is a pathogenic bacterium that causes the fatal Legionnaires’s disease in human. Patients with Legionnaire’s disease usually suffer from pneumonia and fever. The disease is usually transmitted through inhalation of aerosol containing Legionella pneumophila.


Legionella pneumophila is found best grown in warm water, thus, warm water system, for example, cooling tower system, central air conditioning systems, spas and hot springs, drinking water system, etc, are believed to be breeding ground of the hazardous organism.


To prevent Legionnaires’s disease, surveillance and control of large water system should be done regularly. In Hong Kong, Code of Practice for Water-cooled Air Conditioning Systems published by the Electrical and Mechanical Services Department (EMSD), HKSAR Government, recommended that the cooling tower water should be tested for Legionella spp. monthly or quarterly.


Enviro Labs Ltd. (ELL) holds HOKLAS accreditation for enumeration of Legionella using AS/NZS 3896:2017 or ISO 11731:2017 methods (EMSD recognized methods), providing reliable and accurate data for customers.

Typical Legionella colonies on BCYE Agar

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