The role of wastewater systems in the transmission of healthcare associated infections (HCAIs) has been an interest of mine for several years but it was this paper published in JHI last year which highlighted just how big their contribution could be.  

Papers keep coming to support the link between sinks and HCAIs. This recent paper in JHI, examined rates of HCAIs caused by Pseudomonas aeruginosa in six intensive care units (ICUs) in Ontario, Canada. Specifically, the authors investigated the role of sinks in the transmission of P. aeruginosa HCAIs.

The paper was an enjoyable read as there was real rigor in the methodology relating to the microbiological analysis of the ICU sinks, something which Dr Jon Otter and I have discussed the importance of previously. The study used a combination of microbiological sampling and whole genome sequencing as part of prospective cohort study to investigate transmission. I also really liked how the authors defined important terminology used in the analysis, providing clear differentiation between ICU acquired infections and sink acquired infections.

Over the 10-month study there were 4,263 admissions to the six ICUs involved, and 72 (1.4%) P. aeruginosa HCAIs were identified. Unsurprisingly patients who were colonised with P. aeruginosa were more likely to develop and infection and infected patients spent longer in ICU. Analysis of P. aeruginosa HCAIs found that 5-7% of infections came from a sink reservoir. The authors concluded that this rate of infection was likely to be underestimated due to challenges with sampling of the environment and when assessing patient acquisition. The authors also point out that toilets were not included in their sampling analysis, something which I blogged about the risk of recently.  I tend to agree with the authors that this infection rate is underestimated given other studies have reported higher infection rates.

To conclude we have another paper which confirms the role of sinks in the transmission of infections. We need to do more to reduce the risk of these transmissions given the burden to patients and the drain on our healthcare organisations. An additional day stay in ICU has been estimated to cost £1621. We need more research into cost effective interventions to reduce the risk of transmission to reduce the sink and infection burden on our healthcare organisations.