Legionella pneumophila bacteria causes Legionnaires disease; a lung infection, although uncommon it can be very serious. It can be contracted by inhaling tiny droplets of water from things such as air conditioning. It can be found in natural water sources, in this state the bacterium poses no threat to human health. However, this threat changes in temperatures of 20 to 45°C, the bacteria can grow and if inhaled can cause Legionnaires disease.

Here at ALS, we offer two categories of Legionella testing; the traditional culture enumeration method including our award winning MALDI-ToF instant confirmation, where results are reported in 10 days and additionally by Rapid Detection via Polymerase Chain Reaction (PCR) which a presence of Legionella can be reported within 24 hours of sample Receipt. This method is a valuable tool for establishing risk under emergency or outbreak situations and is critical in preventing the spread of infection.

Both methods can be used for the identification of Legionella pneumophila and Legionella species, with the MALDI-ToF providing a full Legionella speciation. ALS require 24 hours’ notice for PCR analysis where possible and request two bottles per sample to allow for the 10 day culture & speciation method to quantify results.

Sampling / Technical information.

In relation to current guidance on Legionella sample sizes and the effect this has on the accreditation of reported results. We wish to confirm that the preferred sample size is 1 litre for Legionella analysis. Current HSE guidance on the subject (HSE 274, parts 1 and 2) gives very specific advice regarding action levels following the sampling and reporting of results, these action levels are given in Legionella bacteria cfu per volume. As such, ALS prefers that a 1 litre sample is provided so that positive results can be given in cfu per volume, fully accredited. UKAS guidance states that for samples where less than 1 litre has been sampled, an calculated positive result can be provided in cfu per volume, but this is not accredited.

ALS provide 1 litre sample bottles for Legionella analysis (Bottle code STL 14). Please note that, regardless of sample size, where samples are free of Legionella, a negative result can be reported as accredited with the associated volume recorded. 'Both methods can be used for the identification of Legionella pneumophila and Legionella species, with the MALDI-ToF providing a full Legionella speciation. ALS request two bottles per sample where PCR analysis is required alongside the 10 day culture & speciation method to quantify results.

For more information on Legionella analysis, sample containers, or for any other query, please contact us here, or contact your Client Service Co-Ordinator for further assistance.

For more information and futher reading, please click here or Contact Us on: Info.UKEnviro@alsglobal.com