WATER HYGIENE AND SAFETY – SPECIAL REPORT


What are the barriers to safe water in healthcare?


Jimmy Walker, of water hygiene and safety consultancy, Walker on Water, who previously worked for Public Health England as a scientific leader in Water Microbiology and Decontamination, and Dr Mike Weinbren, a Consultant Medical Microbiologist at Sherwood Forest Hospitals NHS Foundation Trust, discuss some of the fundamentals of best practice in keeping hospital water supplies in a safe, clean, and hygienic condition, and minimising the risk of their colonisation with potentially harmful waterborne bacteria.


Water systems in healthcare buildings are inherently complex, and the quality of the water is difficult to control. Water delivered by the water supply company will be wholesome, to comply with quality requirements and ensure that it does not present a health hazard. However, wholesome water is not sterile, and may contains many different types of bacteria, including Legionella spp, Pseudomonas aeruginosa, and non-tuberculous mycobacteria, albeit in low numbers. Once these organisms enter the building water system, they can proliferate to an extent that they will pose a risk to the occupants, and particularly the immunocompromised or those in high- dependency units. This article sets out to discuss and graphically demonstrate the


barriers to safe water in healthcare, and to describe inherent risks and hazards, including of human factors, and how a well-managed and trained Water Safety Group can identify and control these issues.


Introduction


The water cycle of a healthcare building is an immensely complicated system, requiring good design, correct selection of components, a hygienic building, and monitoring, maintenance, and management. The bacterial journey probably started in the oceans of our planet billions of years ago. Thus, water is the bacteria’s primary kingdom, and it should be of no surprise that they have developed adaptations to this


Sources of contamination of hospital water systems.


1 Water quality in a hospital Hospital water has rich microbial flora, including Opportunistic Plumbing Premise Pathogens (OPPPs) which will produce biofilm if conditions are not controlled. These include: • Legionella, Pseudomonas aeruginosa, Stenotrophomonas maltophilia.


• Mycobacterium spp. • Burkholderia cepacia. • Cupriavidis spp. • Methylobacterium spp. • Sphingomonas spp. • Acinetobacter baumannii. • Amoebae, fungi.


2. Poor hygienic practices during construction


Poor hygienic


practices, such as not capping water pipe ends, contaminated tools, disposal of contaminated materials in water system, non WRAS- approved materials.


3. Connection to contaminated water supply


Contamination may occur through connection to an already contaminated water system (i.e. adding on a new building), or in some cases water systems were filled from a fire hydrant.


8 2 Figure 1: Overview of some of the inherent microbial risks in water systems. December 2020 Health Estate Journal 15 1


4 Contaminated components coming on site


Components arrive on site pre-contaminated due to water testing during the manufacturing process or being poorly stored/packaged.


6. Poor hygienic maintenance practices


Lack of infection control training, failure to segregate tools into dirty and clean etc.


Hospital


Water tank


5. Lack of cover on water tank allowing ingress of bacteria


CASE STUDY


The inadvertent use of a sewer drain unblocking coil – previously used on the hospital main sewer without decontamination – in the hospital main kitchen, resulted in a hospital-wide outbreak of a highly antibiotic-resistant organism contaminating salads.


7. Outlet contamination and retrograde contamination of water system


Contaminated body fluids inappropriately disposed of in sinks, and drain organisms growing up drains, combined with poor cleaning practices (i.e. cleaning drain then outlet) or splashing/aerosols reaching an outlet, may contaminate the outlet and emerging water, or lead to retrograde contamination of water systems.


8. Contamination with drain organisms


The drainage system provides a superhighway for organisms to spread across the hospital. Blocked drains are very common in hospitals. Drain organisms can grow as biofilm from the siphon up to the sieve in a sink at a rate 1 mm/hour. Highly antibiotic-resistant organisms are emerging from sink drains (ward and kitchen areas), toilets, and showers.


environment, including the ability to grow as a biofilm.1


The first step in biofilm


formation is adherence to a surface, but once bacteria have a foothold, their sloughing or exfoliating from that surface turns the water system into a niche breeding ground. The biofilm can be inherently resistant to control strategies, resulting in repeated re-seeding until those biofilm cells are killed or the biofilm is eradicated.2


The barriers to safe water in healthcare may be seen as the microbes themselves. However, because bacteria are present, and it is neither possible nor desirable to produce large quantities of sterile water, knowledge on how to design and manage safe water systems safely has been developed in guidance documents.3,4


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