Efforts to tackle contamination of sinks in hospitals are heating up

Hospital sinks are increasingly recognised as hotspots for potentially troublesome microbial contamination in hospitals. A recent study in the Journal of Hospital Infection from Nagasaki University Hospital in Japan sheds light on an innovative solution: drainpipe thermal disinfection units (DTDUs). These compact devices heat sink drainpipes to over 100°C, aiming to suppress bacterial growth where traditional cleaning and disinfection methods fall short.

The study, conducted in the hospital’s intensive care unit (ICU), compared bacterial colonisation in ten newly installed metal sink drainpipes, some equipped with DTDUs and others left as controls. The sinks were either used for cleaning oral care devices or staff handwashing. All sinks underwent routine cleaning with ethanol wipes and weekly sodium hypochlorite flushing. Additionally, oral care sinks received daily foam-type disinfectant. A couple of points on the setting. Firstly, the provision of sinks dedicated to the cleaning of oral care devices is an interesting facet of the study - this isn't something that we have in UK settings! Secondly, the measures already being taken to manage sink / drain contamination, with routine chemical flushing, is more than we'd currently do.

Over six months, researchers collected biweekly samples from the drainpipes, analysing bacterial load and resistance profiles. DTDUs significantly reduced bacterial colonisation in both oral care and handwashing sinks. Notably, Pseudomonas aeruginosa, often a persistent pathogen in sinks, was absent in DTDU-equipped oral care sinks. Carbapenemase-producing Enterobacterales (CPE) were found only in control handwashing sinks, not in those with DTDUs.

The study also explored the thermal performance of the DTDUs. Using the A0 value (a standard measure of disinfection efficacy) the devices consistently achieved levels effective against a broad range of pathogens. Imaging of the drainpipes revealed slower accumulation of soap scum in DTDU-equipped sinks, suggesting an added benefit in reducing biofilm-friendly environments.

This research highlights an important gap in hospital hygiene: while surface cleaning and disinfection is routine, internal sink components often remain untreated. We know that drain traps and pipes can harbour bacteria that biofilms make less susceptible to removal and disinfection. And these bacteria can then re-enter the patient zone via aerosols or splashback. DTDUs offer a promising, low-maintenance solution that integrates effectively into existing infrastructure.

However, the study acknowledges limitations. It did not assess the direct impact on patient infection rates, and being a single-center study, broader applicability remains to be tested. Still, the findings suggest that thermal disinfection could be a valuable addition to infection prevention and control protocols, especially in high-risk areas like ICUs.

As hospitals grapple with rising antimicrobial resistance and healthcare-associated infections, innovations like DTDUs represent a proactive step forward. By targeting these hidden reservoirs of infection (sink drainpipes), healthcare facilities can strengthen their defences and protect both patients and staff from preventable harm.