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Legionella Testing in Water

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BACKGROUND:

Legionella pneumophila is an airborne pathogen, contained within aerosol droplets, responsible for causing Legionnaire’s disease which has the potential to cause serious disease in people. Some other species have also been implicated in disease events. As such, sampling and testing for the presence of Legionella is included in NSW legislation in both the Public Health Act 1991 and the Public Health (Microbial Control) Regulation 2000.

Eurofins | ams has now been accredited by the National Association of Testing Authorities (NATA) for the testing of water for the presence of Legionella and for heterotrophic plate counts (HPC). Water sources susceptible to contamination include, cooling towers, spas and shower heads and any other source of warm stagnant water.

Heterotrophic plate counts can provide an overall indicator of the quality of the water and the effectiveness of any biocide treatment.

Testing of Legionella is performed to meet the requirements of the current Australian Standard AS/NZS 3896: 2008. 

For further information about regulatory requirements please click here.
 

PRINCIPLE OF THE TEST:

Samples are plated using 2 different selective agars to enable the detection of Legionella species in the presence of other competing bacteria. The samples are also subject to temperature and acid tolerance treatments to optimise recovery.

Initial incubation is carried out for up to 7 days, with the plates checked for typical growth after 4 days. If typical colonies are detected, they are then streaked onto the confirmation media for up to an additional 3 days.

If typical reactions are seen on the confirmation media, the colonies will then be tested using a latex bead agglutination test kit. This test enables us to determine whether or not the more pathogenic strains are present.
 

METHOD REFERENCE:

  1. Australian Standard (AS) 3896
  2. Australian Standard (AS) 4276

SAMPLE REQUIREMENTS:

A sample size of at least 100ml should be collected. Samples should be delivered to Eurofins | ams the same day in an insulated container.

TURNAROUND TIME:

HPC - 2 days

Legionella - Time will depend on the quality of the water being examined. Negative results with no confirmation required wil take 7 days. Results requiring confirmation will take up to 10 days