WATER SYSTEM SAFETY
Rapid testing technology puts London Trust in control
With input from the Trust’s associate director of Engineering, Louise Clark, Nigel Otter, Marketing manager EMEA at IDEXX, discusses Guy’s and St Thomas’ NHS Foundation Trust’s successful use of two of the company’s rapid microbiology systems to test for, and identify, Legionella and Pseudomonas aeruginosa, ‘in-house’, in the water systems of its two largest London hospitals. Using this testing technology has enabled the Trust to implement, and confirm the impact of, remedial actions in the shortest possible timeframe.
Healthcare estates and facilities managers must be alert to the dangers of waterborne bacterial contamination, as it has the potential to lead to serious infections, especially among immunocompromised patients, such as the elderly, people undergoing treatment for cancer, people in burns units, or premature infants. Rapid, accurate, and regular testing of water systems for bacteria such as Pseudomonas aeruginosa and Legionella is vital to ensure that any contamination is detected as early as possible, so that remedial action can be initiated before any risk to patient safety arises. Louise Clark, associate director of Engineering at Essentia, part of Guy’s and St Thomas’ NHS Foundation Trust, in London, explained: “Water services are there to support clinical care, and it is therefore imperative that outlets remain in use. Across our estate, we have 10,000 thermostatic mixing valves (TMVs) and approaching 18,000 outlets. So, as a Facilities manager, if you are co- ordinating the response to a Legionella or Pseudomonas problem, you cannot afford to waste any unnecessary time before determining the appropriate steps of remedial action.”
In-house testing “A few years ago, at Guy’s and St Thomas’,” she continued, “we had a problem with the water system in a number of areas of the organisation. At the time, we were using a specialised water contractor to undertake the testing. This was time-consuming and potentially risky, as it allowed issues to remain within the system for a longer period, and possibly to develop while we waited for the results. This led to the deployment of many point-of-use filters, and to us taking some outlets out of use, which presented a problem in itself, as they would be declared ‘little-used outlets’, having the potential to grow bacteria and become deadlegs. We wanted to speed up the process of returning these outlets back to normal use.”
Decanting the pre-weighed IDEXX Pseudalert reagent into a water sample. The Trust turned to IDEXX, a
manufacturer of rapid water microbiology testing methods. Louise Clark, and her director of Engineering, had previously used these the company’s systems, including Pseudalert. Psdeudalert is used as a method to enumerate Pseudomonas aeruginosa bacteria in water under the ISO international standard for 24-hour detection of Pseudomonas aeruginosa in water (ISO 16266-2:2018). Samples can be processed in less than one minute, and the results are available the next day without additional confirmation steps, with interpretation of results achieved through observable fluorescence after incubation.
Speed of results A trial was run with Pseudalert to demonstrate the speed at which results could be delivered. “We were able to get quicker confirmation of the effectiveness of our remedial actions,” explained Louise Clark. “IDEXX kindly lent us some kits and trained the staff in their use, and within five to six weeks we had approved the
equipment and purchased systems for both sites.”
She added: “Using the IDEXX tests puts
us in control of the whole process, and we can ensure that each stage is conducted correctly, unlike when external contractors are used, and there are concerns as to whether samples are being taken correctly, and maintained within the correct temperature range throughout the transit stages – from sample point to laboratory. “When we undertake the testing in-
house, we can control the samples from the point at which they are taken to the point at which they are read – ensuring that all the correct parameters are followed throughout the process, and receive confirmed results within a 24-hour period. In contrast, it might take up to a week using contractors and an external lab.”
Advantages of rapid, in-house testing for Guy’s and St Thomas’ With the vast number of outlets, and potential sites for contamination, the Trust uses IDEXX tests on a regular basis
January 2023 Health Estate Journal 43
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