The healthcare built environment constitutes a major transmission route for bacterial, viral, and fungal pathogens among patients, clinical staff, visitors, and contractors. Evidence from the COVID-19 pandemic underscored the impact of suboptimal ventilation systems, limited availability of isolation (side) rooms, and inadequate decontamination facilities in exacerbating hospital outbreaks.
Within the NHS context, these deficiencies significantly impeded efforts to control infection transmission. The CLEEEN study demonstrated that implementation of enhanced cleaning protocols for shared medical devices resulted in a 34.5% reduction in healthcare-associated infections (HCAIs). These findings highlight the importance of appropriate healthcare facility design and engineering controls as pivotal factors in optimising infection prevention and safeguarding the health of hospital occupants.
The widespread use of antibiotics over recent decades, coupled with a deceleration in the development of novel agents, has led to the emergence and proliferation of multidrug-resistant (MDR) bacteria. In hospitals where last resort antibiotics are increasingly used in vulnerable patients, these are excreted predominantly unchanged in their urine, faeces and other body fluids, all of which are going down the drainage systems of hospitals, along with many types of MDR bacteria that such patients will carry, along with chemical and disinfectants used if hospitals.
Drains in healthcare, therefore, have become the perfect incubators for harbouring and generating different types of antimicrobial-resistant (AMR) organisms.
Infections with AMR bacteria are associated with higher mortality rates, making AMR one of the most significant threats to modern medicine. The unchecked spread of AMR could render routine surgical procedures, such as joint replacements, or oncological treatments unsafe due to heightened infection risks.
Studies have demonstrated that splashing and aerosolisation generated from pressure transients from drains at distant sites can disseminate these organisms onto patients, healthcare personnel, and medical equipment, thus facilitating further transmission within the healthcare environment. The cost of treating such infections and managing these outbreaks runs into millions of pounds that can be better used in healthcare if such infections can be prevented.
Our own experiences in managing a recent large outbreak of AMR superbugs at Frimley Health NHS Foundation Trust has helped us recognise the critical role of water and wastewater in hospital built environment in the transmission of many different types of pathogens. We adopted a water-free approach for the first time in the UK and the NHS, to combat a type of AMR superbug called CPE (Carbapenemase-producing Enterobacterales).
This approach was first pioneered by Hopman et al., in the Netherlands. At Frimley Health, we have adapted this approach and enhanced it to include water as well as wastewater safety and made it applicable to an NHS setting. A better terminology for water-free care may be water and wastewater-safe environments.
This involves removing excess handwash basins (HWB), especially those close to patients and their equipment, using HWB designs that reduce splashing, and ensuring that any water that reaches patients has not been in contact with wastewater (for example, water use for drinking with jugs in contact with drains, or water used for bathing or cleaning wounds). Water itself carries many pathogens, which can be dangerous to very sick patients, hence engineering out such risks protects patients.
Based on the above infection risks, the 5 design mistakes to avoid in healthcare include:
1. Wastewater systems in healthcare: blockages in drainage systems are common occurrences in hospitals. These could include HWB drain, shower or macerator blockages. Some hospitals experience this soon after opening a new build or a refurbishment project. Such blockages present a significant risk for transmission of dangerous pathogens that can be expected in hospital drainage systems. The drainage infrastructure has not undergone substantial reassessment over several decades as risks of transmission of pathogens have gone unrecognised until now, when we are faced with superbugs that has made tracking infections easier. Once installed, these drainage systems are difficult to fix. Getting it right the first time is critical.
2. Water distribution system: The way water is stored, circulated and heated in healthcare and the way these systems are designed and installed have a significant impact on HCAIs. Several recurring design and installation errors contribute to microbial proliferation: for instance, the early filling of water storage tanks—often weeks or months before a facility becomes operational—can foster stagnant conditions conducive to bacterial growth. Complex hot water return loops frequently present insurmountable challenges for system balancing, resulting in uneven temperatures and increased risk of colonisation by opportunistic pathogens. Furthermore, pipework destined for potable water is often exposed to environmental contaminants, such as dust and construction debris, prior to installation unless rigorous protective measures are implemented. The selection of unsuitable building materials—including sealants like plumber’s putty, which can promote microbial adhesion and biofilm formation—exacerbates the risk of contamination. These errors, once embedded within the infrastructure, are prohibitively costly and technically challenging to rectify, underscoring the importance of precise engineering and vigilant oversight during the initial design and construction phases.
3. Periphery of the water system: Installation of an excessive number of hand wash basins, especially in close patient proximity, in clean areas such as treatment rooms where these are not required, along with poorly designed or installed fittings (HWBs with drains that are directly below taps, for example, that increase splash risk of wastewater pathogens).
4. Areas for decontamination of equipment and storage: Dedicated areas with flow of contaminated equipment from dirty to clean without crossover and with availability of safely designed built environment facilitates the reduction of HCAIs as demonstrated in the CLEEN study. Areas for storage of all types of equipment needs factored in at the time of design.
5. Ventilation: Adequate ventilation to prevent transmission of air borne pathogens is paramount as evidenced by the pandemic. Supply grills placed close to the exhaust, exhaust grilles placed close to windows of adjacent rooms which may have severely immunocompromised patients are errors to be avoided.
To address these issues, the Healthcare Infection Society (HIS) has announced the formation of the Built Environment Infection Prevention Initiative (BEIPI)
To address these issues that are costing patients' lives and NHS in millions of pounds in resources, the Healthcare Infection Society (HIS) has announced the formation of the Built Environment Infection Prevention Initiative (BEIPI) - a cross-sector taskforce dedicated to embedding infection prevention principles into the design, construction and operation of healthcare settings. Join the Built Environment Infection Prevention Initiative (BEIPI) dedicated mailing list which will include future updates, publications and events.
HIS also run an online course delivered by IPC professionals and engineers, Water safety in healthcare | Healthcare Infection Society - Healthcare Infection Society - designed for all those involved in water safety in the built environment including IPC teams, Estates, Clinical microbiology and infection specialists, Engineering, Construction, Design, Project, Procurement and Executive teams.