WATER SYSTEM SAFETY
to monitor its water system. Louise Clark explained: “We have found that the use of IDEXX Water’s testing methods significantly helps reduce any downtime encountered with problematic outlets. The simple tests are fast, cost-effective, and put us in control. “When we have a particular issue, we use the IDEXX tests to identify and locate the problem, and to get a speedy resolution. The kits quickly determine the conditions in the water system for bacterial growth, and indicate whether we have eliminated them with our remedial actions. This means that the outlets can then be returned to use quickly and more cost-effectively.” “Some of my colleagues were initially
sceptical,” Louise Clark continued, “but they have been won over, and are now more readily accepting of the methods, and the results they deliver. The clinical staff and infection prevention and control teams are supportive of the rapid results of in-house testing. “Recognising that there is a requirement
for continual monitoring and testing, we will continue using these rapid technologies to support and understand the extent and impact of any contamination, and of our remedial actions. Taking this into account, we have amended our standard operating procedures in the Trust to include the use of IDEXX rapid testing methods alongside accredited procedures.”
Challenges during the COVID-19 pandemic Faced with a potentially major Legionella issue at the height of the COVID-19 pandemic, and challenges in coordinating external contractors to sample and test water, the Trust again turned to IDEXX for assistance. The Facilities team had introduced
enhanced flushing procedures throughout the estate wherever lower utilisation had been identified. However, one particular
Associate director of Engineering at Guy’s and St Thomas’ NHS Foundation Trust, Louise Clark.
instance of lower usage was not brought to the attention of the team. This concerned two lower floors of a non- patient area in one building, which saw a reduction in outlet use when staffing levels reduced. Subsequent monthly routine testing of the area showed positive results for Legionella. While the UKAS-accredited tests take
up to two weeks to confirm the presence of Legionella, through the relationship with IDEXX, and the routine use of, and confidence in, the previously proven Pseudalert method, the Trust trialled the use of the IDEXX Legiolert test to see if the problems could be identified and resolved more effectively. IDEXX launched Legiolert in Europe and North America in 2017. It is a liquid culture method using most probable number (MPN) that is highly sensitive for the confirmed detection of Legionella pneumophila (the primary cause of Legionnaires’ disease) in water. The
Legiolert method is certified by AFNOR ‘NF validation’ (IDX 33/06-06/19), and has been published by ASTM International as the ASTM D8429-21: Standard Test Method for Legionella pneumophila in Water Samples Using Legiolert. The method delivers confirmed results within seven days, which can be twice as fast as the conventional plate culture testing methods and, as with Pseudalert, samples can be processed typically within one minute, with the presence of contamination indicated by a colour change of the sample after incubation.
The extent of the contamination “As the person responsible, I needed to know what action was required,” said Louise Clark. “We began with a small area. As we investigated back, we increased the area, supporting the UKAS-accredited testing with extensive Legiolert testing. We had a concern about the extent of the contamination, so we took an initial batch of over 120 additional samples one Friday morning, which were couriered immediately to IDEXX’s laboratory, which ran the tests for us. IDEXX was very supportive, and the speed of the method meant that we had preliminary results early the following week. This gave us a much clearer view of the extent of any potential issues.” The samples were run alongside UKAS-
accredited testing to determine whether there was correlation between the results. The comparison was very favourable, which allowed Louise Clark’s team to quickly pinpoint contamination issues, undertake rapid remedial actions, and check how effective they had been.
The IDEXX Sealer PLUS – a device for sealing IDEXX Quanti Trays prior to incubation and quantification of bacteria counts.
44 Health Estate Journal January 2023
Legiolert system After this initial batch, the Trust installed an in-house Legiolert testing system to support the processing and incubation of the high volume of samples required. Louise Clark said: “This was all in an attempt to reduce the timescale that was faced to take remedial action. It allowed further interventions to be deployed where necessary, much earlier than would normally be the case.” Leading water hygiene specialist, Dr Paul McDermott, provided technical support to the Trust on COVID-19-related contingency projects involving water-critical areas. He said: “When testing routinely in hospitals, you will sometimes find Legionella. Usually, it does not result in an infection, but finding the bacterium in hospital water systems should always result in some form of internal investigation, and in some hospital areas its presence is particularly significant. “Positive test results can mean that part of a water system is taken out of use temporarily, and, like everything else, this has a resulting cost – even if a single tap is taken out of use, there’s an associated cost. UKAS-accredited laboratories will
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