INFECTION CONTROL


Uncovering hidden contamination pathways


Despite decades of advances in cleaning, sterilisation, and clinical protocols, healthcare-associated infections (HAIs) remain a persistent challenge. While significant progress has been made in controlling surface and instrument-related risks, increasing attention is now being given to the role of the built environment itself, where infrastructure systems such as water, air, and drainage operate continuously and may act as sources of microbial contamination. Here, Jørn Terkelsen, founder and CEO of Dolphin Care, looks at whether infection prevention strategies are addressing all relevant pathways of contamination within clinical environments.


In many healthcare settings, responsibility for infection prevention is divided between clinical teams and estates or facilities departments. While this reflects organisational structure, it may also create gaps in how environmental risks are addressed.


Clinical teams focus on patient-facing interventions such as cleaning, disinfection, and aseptic technique. Meanwhile, infrastructure systems, including ventilation, water systems, and drainage, are often managed with a focus on performance and compliance, rather than microbiological impact. As a result, certain contamination pathways may be


under-recognised. Even in well-managed environments, microbial reservoirs within infrastructure systems may persist and contribute to ongoing contamination.


Water systems and hidden reservoirs Hospital water systems have received increasing attention in recent years, particularly in relation to biofilm formation within plumbing and drainage systems. Biofilms provide a stable environment in which


microorganisms can survive and proliferate, often protected from routine cleaning and disinfection practices. In clinical areas such as endoscope reprocessing rooms, sinks may therefore act as persistent environmental reservoirs. While surface cleaning reduces contamination on visible surfaces, it does not address microbial load within underlying infrastructure. This creates the potential for repeated recontamination of the surrounding environment. Recent work published in the Journal of Hospital Infection has further highlighted the role of sinks as potential sources of environmental contamination. Studies have demonstrated that microorganisms present within drainage systems can be dispersed into the surrounding environment through splash events, including Gram- negative organisms and, in some cases, strains associated with patient infections. These findings reinforce the importance of considering not only visible surfaces but also underlying infrastructure when addressing persistent contamination.


Case study: identifying the source of contamination A clinical investigation in a hospital setting highlighted the importance of looking beyond surfaces and equipment when addressing persistent contamination. Despite thorough cleaning protocols, recurring


microbiological findings prompted further investigation. Initial focus was placed on clinical equipment and procedures, but no clear source could be identified.


Attention then shifted towards the surrounding


infrastructure, including the drainage system. Following installation of UV-C-based water trap technology targeting the drainage system, no further cases were detected over a period exceeding three years. This shifted the focus from clinical processes to


the surrounding infrastructure as the likely source of contamination, illustrating how hidden reservoirs may influence outcomes in ways that are not immediately visible.


September 2026 Health Estate Journal 79


Above: Clinical sink environment used during manual cleaning procedures, where drainage systems may act as persistent environmental reservoirs.


Left: UV-C-based intervention installed within the drainage infrastructure beneath a clinical sink.


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