WATER SYSTEM HYGIENE AND SAFETY


Hospital birthing pools and cooling towers have both been associated with Legionella outbreaks.


tiling, and in dips of uneven flooring. This water could harbour Legionella bacteria long after the visible flood has subsided. In addition, puddles in high- traffic areas, where perhaps trolleys are wheeled through, could launch Legionella-contaminated aerosols into the air, where they can be inhaled by the unsuspecting vulnerable.


n Unused facilities in closed wards – any water outlet that is used either infrequently, or not at all, is a serious risk for Legionella growth, as this too creates stagnation. Closing wards due to structural risks, and then being forced to use them again – because of overcrowding – would put patients at risk of infection unless these environments have been re- commissioned correctly.


n On-site construction projects – during construction work, the plumbing systems of a building can be disrupted or disconnected, and sections may be temporarily taken out of service, leading to stagnant water becoming trapped in pipes and fixtures. This stagnant water can then provide an ideal breeding ground for Legionella bacteria. Additionally, construction activities such as drilling and cutting can create dust and debris, which can contaminate water systems and encourage biofilm (slimy communities of sessile microorganisms including bacteria, algae, and protozoa) to develop on the inside of pipes. The majority of Legionella, if present, will reside within


‘‘


this biofilm, which can also provide ideal nutrients for Legionella growth. When the water system is then put back into service, this contaminated water can be dispersed throughout the building, leading to potential exposure of patients and staff to the bacteria.


n Cooling towers maintenance that are out of compliance – because of their ability to spread Legionella over a wide area, cooling towers are regarded as one of the most dangerous and heavily regulated sectors in the water treatment and Legionella control industry. The aim of these systems is to extract heat from a building and dissipate it into the atmosphere via an evaporative process. The heat and evaporated water then flow out the top of the tower in the form of a fine cloud-like mist. If windows are open to give patients some much-needed fresh air, they could be unknowingly breathing in Legionella- contaminated aerosols. A study was conducted by the CDC (Centers for Disease Control and Prevention) after a significant Legionnaires’ disease outbreak caused by cooling towers in the US in 2015. Legionella species DNA was found in 88.5%4


of the


cooling towers tested, and specifically Legionella pneumophila DNA was detected in nearly 50%. Therefore, the maintenance of these systems is essential.


Legionella pneumophila is the species responsible for approximately 90%


During construction work, the plumbing systems of a building can be disrupted or disconnected, and sections may be temporarily taken out of service, leading to stagnant water becoming trapped in pipes and fixtures. This stagnant water can then provide an ideal breeding ground for Legionella bacteria


46 Health Estate Journal May 2023


of Legionnaires’ disease cases.5 L. pneumophila is divided into 15 serogroups. and serogroup 1 is proven to be the most prevalent disease-causing variant. In fact, the ECDC (European Centre for Disease Prevention and Control) Annual Epidemiological Report for 2020 highlighted that Legionella pneumophila serogroup 1 was the cause of 83% of cases reported between 2019 and 2020 alone.5


A greater focus on Legionella hazards needed Care-giving buildings that are falling apart need to be a focus for the government, and that focus needs to be wider than just the immediate risk from falling debris or mould. The focus should include the hazards of waterborne pathogens, especially Legionella pneumophila, which is triggered by this very state of disrepair. While a refurbishment and construction programme could reduce the risk of Legionella in the long term, there are many well-known specific Legionella risks associated with this. Several phases of a construction


project can increase the risk of Legionella proliferation. These include excavation, inadequate building water system recommissioning, construction equipment with water reservoirs, re-pressurisation, demolition activities, underground utility connections. and water main breaks. Alarmingly, in a report by the International Journal of Environmental Research and Public Health, more than three-quarters of Legionnaires’ disease cases linked to construction activities were found to be in healthcare buildings.6


An overwhelming


71% of these healthcare settings involved acute care hospital operations.


Construction activity risks In the same report, the top construction activity contributing to Legionnaires’ disease cases by frequency of occurrence was excavation (38.7%).6


The physical process of excavation can cause bacteria


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