That sinking feeling


I’m at ECCMID in Amsterdam currently listening to a nice report of an OXA-48 Klebsiella pneumoniae outbreak in Gran Canaria in which sinks were found to be contaminated and replaced. Earlier today I listened to a nice paper on how sinks that drain slowly are more likely to contaminate the local environment for up to 1 metre from Paz Aranega Bou who, together with Ginny Moore and other colleagues has published this nice paper . So many papers on sinks now and I do wonder if we have lost sight of what they do and what they really are.

Another recent paper from Sylvia Munoz-Price’s group which reported that proximity of a sink to a toilet was related to the level of MDR gram-negative (in this case, Klebsiella pneumoniae Carbapenemase) contamination. In this paper the authors showed that the sink closest to the toilet was more contaminated than the sink in the same room but much further away. The authors suggested that this could arise from ascending colonisation of the pipework (shown in other papers such as this one from Amy Mathers group) , toilet plume (as in this paper) or possibly hand hygiene by a staff member or patient.

My reaction to this? Well for a start I’m absolutely delighted that a sink beside a toilet should become contaminated with MDR gram-negatives. It’s sort of the point of a sink, to remove organisms from the hands. A sink is not an item of purity, it is a waste disposal point and should be expected to become contaminated. If it were not, it would suggest to me that no hand hygiene was occurring.

I’ve been mulling this over quite a lot recently and in the past. Do we really need so many sinks in clinical areas and are they well-placed? It is tempting to place a sink beside somewhere clinically significant to make hand hygiene easy, however this means that some critical equipment may be in the locality and could become contaminated during a simple process such as hand hygiene. Another study from Amy Mathers group that I really liked looked at the use of a sink in a critical care area through the use of video which showed that hand hygiene was only 4.38% of all activity at the sink. In the patient’s bathroom, it was less at 2.5% although nearly 10% of all activity was the placement of the patient’s personal items in the sink, thus potentially contaminating all of them and a staggering 12.55% of all activity was the placement of medical items in the sink. All of this calls into question the need for hand sinks, or possibly to completely revise our strategies and maybe even to consider removal as they seem to be being used as somewhere to put something.

In this last Mathers study, 56 of the activities would involve putting nutrients down a sink. We use a sink to remove pathogens from our hands. We should not be amazed that sinks become contaminated, however education is needed for staff, possibly even a new programme of sink safety involving keeping a zone around a sink free of equipment, possible removal of sinks from the immediate clinical environment in a critical care area and importantly, education of the staff who use and who clean a sink on the role that they may play in pathogen transmission. Not putting a patient’s personal items in one would be a start. Simple replacement will not do however, as if the behaviours continue as before (and in the case of hand hygiene after using the toilet you would hope that they would) then the problem will recur and in many ways, it is probably a good thing that it does.


One thought on “That sinking feeling

  1. Dear Mr. Kiernan,

    I thank you for this well-written post in such a fruitful blog. In my work as an MD-PhD candidate in IPC in Geneva, I had to review the litterature on this topic. And I observed that we currently face an increasing mass of studies on the role of sinks in outbreaks of resistant but also susceptible (we often forget them) gram-negative Enterobacteriaceae.

    Sinks in clinical areas are now a place where “clean” and “dirty” activities are mixed (as the toilet for patients). Furthermore, the contamination of nearby sterile equipment (splash effect at ~1m) is well accepted now. So we agree sinks in clinical areas, and particularly in ICU hosting vulnerable patients might be a problem.

    French clinicians rethinked the design of sinks (increased activity space, …) to reduce the splash effect and subsequent contamination. We also can place barriers between sinks and sterile equipment disposal, provide some recommandation to avoid nearby disposal of sterile equipment, … But do we really supress the risk ? Are we sure that recommandations are followed ?

    Other solutions are fancy technologies, including specifically aerosol reducing traps, sink copper pipes, self-disinfecting sink traps ( But I don’t think these solutions do not address the root of the problem, and constitute an expensive solution without the guarantee to eradicate all risk of contamination. I would wait more efficiency studies on these solutions.

    Other colleagues from Spain completely deleted sinks from clinical areas. This, entirely question the need for sinks in ICUs. (​ I would say we really have to rethink the presence of sinks in clinical areas of critically patients, which are particularly susceptible. After for non-ICU wards, it remains another question for me (different needs for sinks).

    So for my opinion on the subject, in a first place some activities involving sinks, such as toilet, could be water-less in order to avoid contaminating the sink and being contaminated by the sink. In a second place, building/renovating a hospital should involve infection control practitioners to adopt the ideal design and place for sinks. I think the question of sinks should be thinked and weighted according to the requirements of sinks and vulnerability of patients. So I would see different solutions for ICUs and wards. I entirely agree with you that more sustainable solutions than mere syphons/sinks replacement should be researched.

    Kind regards
    Romain Martischang


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