A fantastic new study from Brett Mitchell’s prolific group in Australia has recently been published in Lancet Infectious Diseases and the results are pretty spectacular. A fairly low cost intervention of an extra 3 hours of cleaning and disinfecting shared medical equipment each day resulted in a whopping 35% reduction in HCAI in a randomised controlled trial. I’m delighted to say that Prof Brett Mitchell will be introducing an IPC Journal Club on this study next Wednesday (register here).

The study was a nicely designed single centre stepped-wedge cluster randomised controlled trial. It was undertaken in 10 wards in an Australian hospital over 9 months. This study design is the best we can get with an IPC intervention affecting multiple patients simultaneously, where cross-transmission is one of the outcomes (an individualised RCT – the type of study that you would do with a drug – won’t work because you can’t randomise at an individual level, hence cluster randomisation). The ‘stepped-wedge’ design means that the intervention is staggered in time, which allows individual clusters (in this case wards) to act as their own control.

The intervention consisted of :

• an additional of 3 hours cleaning and disinfection (using combined detergent/disinfectant wipes) focussed on shared medical equipment for each ward per day. Shared medical equipment was defined as non-critical medical devices that made contact with intact skin (e.g. commodes, blood pressure cuffs)
• education on cleaning techniques
• using a UV fluorescent marker to monitor cleaning thoroughness with feedback to staff

The study included around 5000 patients, with an even split between intervention and control. The study team showed that potential confounders such as patient characteristics, hand hygiene, and colonisation pressure were not significantly different between the intervention and control groups.

Key findings:

• In the adjusted analysis, the rate of HCAI reduced significantly from 14.9% to 9.8% (OR 0.62, 95% CI 0.45 to 0.80).
• In the adjusted analysis, the predicted cleaning thoroughness increased from 24.3% to 65.6% (OR 5·94, 95% CI 4.13–8.55).

Some limitations and points for discussion:

• The study was single centre, and may not be generalisable. Also, ICUs were not included.
• Related to this, the baseline rate of HCAI was rather high at 14.9% (I’d expect this to be more in the 5-10% range – where it got to during the intervention in fact).
• The study had a relatively short duration, and seasonal variable may have played a factor.
• No evaluation of acquisition of antibiotic-resistant bacteria was included – this is almost certainly due to lack of testing/surveillance to measure acquisition.
• Antibiotic consumption, a key potential confounder, was not mentioned.
• Only 79% of cleaning shifts were filled. This was most likely due to the role being unattractive, and suggests that to implement changes based on this study we will need to think beyond a new “shared medical equipment cleaning and disinfection officer” role because, we may struggle to find people willing to do that job!
• One of the reasons historically for low compliance with cleaning and disinfection of shared medical equipment is responsibility. A fairly recent review showed that there was no defined cleaning responsibility for more than 50% of items of shared medical equipment. And so, the nurses think the cleaners are doing it, the cleaners think the healthcare assistants are doing it, and the healthcare assistants think the nurses are doing it. And so it goes round and round and nobody does it! Perhaps we can use this CLEEN study as ammo to solve this issue once and for all?

I’ve followed the development of the literature evaluating the potential role of surface contamination in the spread of the micro-organisms that can cause HCAI really closely throughout my career. And this is one of the most powerful studies ever published supporting a crucial and still quite under-rated role for surface contamination in the spread of these HCAI-causing micro-organisms. If I asked you what % of HCAI are linked directly to surface contamination, what would you say? <5%? 10?? But 35%?! Not sure many would say that – but this is what this study suggests, because the surface hygiene intervention reduced HCAI by 35%! There are other studies that provide credence to the idea that the link between surface contamination and HCAI may be larger than many would expect. For example, one RCT (albeit one with contentious methodology) showed that the introduction of antimicrobial copper surfaces reduced HCAI by 58%. And a study that I was involved with at Johns Hopkins in the US suggested that patients admitted into rooms disinfected using hydrogen peroxide vapour were 64% less likely to acquire an antibiotic-resistant pathogen than those admitted to rooms cleaning and disinfected using standard methods.

I ran a quick poll on X earlier, and the sample size is small but around 50% of those who responded estimated the proportion of HCAI directly linked to surface contamination as >35%, which surprised me. I’d be interested to see how this question would play out what a larger sample.

I still occasionally hear people say “the evidence supporting the role of surface contamination in the spread of micro-organisms that cause HCAI is a bit weak”. Admittedly, this trope is becoming less and less common. But it’s still out there. And it’s just not true! There are now multiple well-designed studies showing that improving surface hygiene in various ways reduces the transmission of antimicrobial-resistant organisms and HCAI. This CLEEN study. The BETA-D study. And countless well-designed observational intervention studies. I can’t think of many other IPC interventions that have a stronger evidence base.

So, how do we go ahead and implement change based on this study? This study calls for us to review exactly how we clean and disinfect shared medical devices. And there’s a real incentive for investment here, because on the basis of this study, improving standards of cleaning and disinfection of shared medical devices will reduce HCAI and improve patient outcomes!

Remember, Prof Brett Michell will be leading an IPC Journal Club on this study next Wednesday 11^th September at 1000-1045 (UK time) – register here!