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Legionella Testing |
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Background
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. 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.
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.
Sampling
A sample size of at least 100ml should be collected
Samples should be delivered to
Turn Around times
2 days
Legionella
Time will depend on the quality of the water being examined
Not detected result with no confirmation required 7 days
Results requiring confirmation up to 10 days
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