Legionella Testing
Leggionnaires' disease is a form of penumonia that may have severe consequences on the infected, particularly the elderly. People may become infected if the Legionella bacteria is inhaled while breathing, as the bacteria can be dispersed in the air in very fine droplets of water, known as aerosols. The bacteria live naturally in environmental water sources but if they are present in functioning water systems, the risk of infection increases. Infection may spread through air conditioning systems or through contaminated water systems used for showers etc. Control and prevention of the disease is through treatment of the source of infection, i.e. the contaminated water systems.
To regulate and control the risk from exposure to legionalla bacteria two regulations were published under the Public Health Act, namely the Control of Legionella Regulations, 2006 (L.N.5 of 2006) and the Registration of Coling Towers and Evaporative Condensers Regulations, 2006 (L.N.6 of 2006).
The operation and maintenance of water systems involves frequent visual inspections, regular cleaning and in some cases water treatment processes. Inspections need to be carried out at least once a month and must be used as a guide to the efficacy of the system performance. This responsibility lies with the owner or occupier of the premises and these secures must be presented to the competent authority when requested.
As stipulated in Regulation 11 (1) (f) Legionella testing has to be carried out by an ISO accredited lab at least once every six months. Both the hot and cold water systems need to be tested.
It is important to note that microbiological monitoring of water systems for Legionella should never replace good engineering practices, regular maintenance and cleaning programs. Testing is a REQUIREMENT in ADDITION to water engineering. Legionella testing is also important in validation testing prior to the commissioning of the water system. The number of samples required will vary depending on the size and nature of the water system but as a guide cooling towers should be tested weekly for 4 to 6 weeks. For warm water systems, 4 to 6 samples need to be collected from 2 or more locations every fortnight for a period of a few weeks.The verification process could be extended for warm water systems, in particular, by taking samples for heterotrophic bacterial counts.
It is important to note that Legionella testing requires a maximum of 10 days incubation according to ISO 11731, allowing for unacceptable delays in the event of an outbreak. This further corroborates the fact that inspection, cleaning, decontamination or decommissioning of a system should take priority.
It is also recommendable that total heterotrophic counts are taken on a regular basis, in order to be able to detect bacteria present in biofilms within a system. The presence of such bacteria would be an indication of incorrect or insufficient water disinfection and will require action to be taken well before the detection of Legionella.
According to regulation 12 (1) the responsible person (Owner or manager of the establishment) must ensure that the actions following microbiological analysis for Legionella of hot and cold water services are in accordance with the procedures laid down in Schedule 4 of the L.N. and shall immediately inform the health authorities of the situation as required.
We are the ONLY private local lab that can provide Leigionella testing according to L.N. 5 (2006). The same legal notice stipulates that testing and sampling needs to be carried out by qualified personnel in a ISO 17025 lab.
Apart from this BioDNA Laboratory Services will be able to provide risk assessment reports and help its clients, by providing several documentation reports and forms, which need to be kept in a form of a logbook to be presented on the event of an inspection by the authorities.
