Do single rooms prevent HCAI? This suggest suggests YES for norovirus, but no for C. difficile infection and E. coli BSI

There are pros and cons of increasing the proportion of single rooms. One of the commonly-cited pros is a reduction in HCAI. A recent UK study provides some evidence that C. difficlie infection, and MSSA /  E. coli BSIs are not reduced by a move to a hospital with more single rooms, but that norovirus control is more effective when you have more single rooms.

A large UK NHS Trust moved from a multi-site old style hospital with a mixture of Nightingale wards and wards comprised of bays and single rooms with 10% single rooms overall, to a new hospital on a single site with 75% single rooms. The study design was simple: did the move result in a reduction in the rate of healthcare-associated C. difficile infection, MSSA and E. coli BSI, and number of wards closed and bed days lost for norovirus over 3 years before the move compared with 2 years after the move?

The findings are rather equivocal. The incidence of HA-CDI and E. coli BSI declined markedly when comparing the years before vs. after the move. However, the time series analysis could not detect a significant change in rate of decline, or a step-change in rate at the time of the move. This suggests that the incidence of these organisms reduced over the study period for reasons other than the introduction of a hospital with more single rooms. There was no movement in the rate of MSSA BSI over the study period. However, the number of ward closures and bed day losses due to norovirus was strikingly lower after the move to the new hospital. I found the lack of a chart especially challenging in interpreting the data reported in the study!

The findings of this study are reminiscent of a study published in the NEJM in the early 1980s (Maki et al.), which was a similar ‘natural experiment’ evaluating the impact of a hospital move on the rate of HCAI. The Maki study found that moving to a new hospital (and therefore the role of the environment) made no impact on endemic HCAI – and this view stood for a couple of decades! On the face of it, this study supports the idea that moving to single rooms does not reduce HCAI, but I don’t think that it can be seen as the definitive study on this topic, because:

  • There is no control group (what else changed during this period?).
  • The move was not only to a building with more single rooms, but to a new building with a different layout and very probably different staffing levels.
  • Were the right indicators of HCAI included? If we were looking to make any conclusions about the role of single room in preventing HCAI, we’d need to know about the acquisition of colonisation with key pathongens, not sure CDI and BSI. (Worth noting that many BSIs have an endogenous source…)
  • There was a marked reduction in norovirus ‘activity’ in the hospital. Whilst norovirus incidence is notoriously volatile from season to season, the reduction was striking (although, remember, no control group).
  • There are studies with a much better design that do demonstrate a significant reduction in HCAI associated with a more to single rooms. The best example of this is a controlled study by Teltsch et al., who found that moving to an ICU with 100% single rooms resulted in a significant reduction in pathogens associated with ‘exogenous’ transmission and no reduction in pathogens associated with ‘endogenous’ transmission.
  • There was no data to show that the level of compliance with basic IPC practice remained unchanged (e.g. hand hygiene compliance rates, such as they are).

Since this study used nationally reported data, it’s also possible to do something similar on a national level using Fingertips. If you hypothesise that more single rooms = less HCAI, then you ought to see a correlation between the proportion of single rooms in a hospital and the rate of HCAI. However, the Figure below shows that there is no meaningful correlation between the rate of healthcare-associated C. difficile and hospital-onset E. coli BSI and the proportion of single rooms in NHS hospitals. This crude comparison is perhaps confounded by the different  types of NHS hospitals (e.g. specialist acute vs. district general vs. academic teaching), but is thought-provoking nonetheless.

Figure: Rate of (a) Trust-apportioned (healthcare-associated) C. difficile and (b) hospital onset E. coli BSI by acute NHS Trust plotted against the proportion of single rooms with ensuite facilities.


(a) Trust-apportioned (healthcare-associated) C. difficile. R2 = 0.04.

(b) Hospital-onset E. coli BSIs. R2 = 0.03.

In summary then, this study and my dabble on Fingertips support that the proportion of single rooms is not the critical factor in the key HCAI metrics reported nationally. Whilst I am not surprised to see this for the BSIs, I am a little surprised to see this for C. difficile. However, given the rudimentary design of these experiments, we need properly controlled studies before coming to firm conclusions.


6 thoughts on “Do single rooms prevent HCAI? This suggest suggests YES for norovirus, but no for C. difficile infection and E. coli BSI

  1. It would be interesting to find out in regards the assessment of the change of the environment and culture at the ward level.

    We know that context has an impact but also leadership

    Liked by 1 person

  2. Dear Dr Otter;
    Excellent topic on Contact Public Health Infections.
    Dr Sameh Nashid MD
    Consultant in Infectious diseases
    First Hand Expert in C.difficle
    Entrocolitis.Tutored Student of Late Professor J.V.Dowell, Of CDC Atlanta , Georgia, Dicover C.Difficle and First Anaerobic Microbiologist Isolating it in Year 1983.Also Student of Prof Dr John J.Bartlett MD of John’s Hopkins University School of Medicine Head of Infectious diseases. All the Best.


  3. It looks increasingly likely that most E.coli, MSSA plus C.difficile healthcare infections, are caused our own endogenous flora that causes an infection with these flora that we bring into hospital with us. The infection results when we give these bacteria an opportunity to infect us e.g with an IV catheter in place, urinary catheter, antibiotic course or in hospital acquired pneumonia etc, etc. Thus single rooms will not have much effect on decreasing these infections in hospital (good infection control practices, removing catheters, antimicrobial stewardship etc will have an effect however).

    For VRE, most MRSA infections plus healthcare norovirus outbreaks, these are predominately acquired in hospitals, and so this if where single rooms and separating non-infected patients will make a difference. Hence what i would expect studies to show if they break down hospital infections by bacteria and virus types as the cause.

    Its a mistake to lump all healthcare infections together for single room analysis. They are not all the same.

    Peter Collignon, Infectious Diseases Physician and Microbiologist, Canberra Hospital. Professor, Medical School. Australian National University.


  4. I worked in a hospital were wards were changed from 4-6 persons rooms, to rooms with a maximum of 3 persons and more single rooms. We had a concurrent outbreak of norovirus on an old ward and a renovated ward, where the one in the renovated ward was much faster under control. One small observation. which we though was mainly due to the fact that the smaller rooms also had their own toilet facilities which were reached through the rooms, whereas those in the old wards were located in the hallways. I think designs of buildings really could play an important role, because toilets reached directly from corridors, are also more likely to be used by patients from other rooms.

    Apart from this, I somtimes feel that we are focussing to much on single rooms. In normal wards. Single rooms can have detrimental effects too, especially for elderly patients; more confusion, less wellbeing due to less contact with other people, more dangers of falling etc. Imagine the confused patient picking at his IV line, the neighbour alerting the nurse. A real life situation where observations.
    Talking to nurses, they indicate that they need more staff to keep an eye on all patients at all times, whereas hospital administrators do not see that necessity.
    So perhaps there is a compromise that is optimal, not the ends of the spectrum.
    In ICU patients I do believe a physical barrier can significantly reduce spread, because it prevents nurses from ‘turning around and quickly do something for another patient”. In our single room ICU nurses and doctors indicate that it helps as a reminder to deinfect hands between patients, since they have ingrained in themselves the habit of deinfecting their hand before entering a room. Perhaps in wards with more hands-on care, where the procedures done by staff are more likely to result in a HCAI, single rooms have a more benificiary effect. For instance, a wound infection is more likely to from a hand contaminated by MRSA than a HAP. The latter might result form the fact that a patient is not activated & mobilised enough.

    To truly asess the effect of single rooms, would be a complex study. And I strongly feel that it should not be done with only the focus on HCAI, it should be done with a focus on patient safety as whole.

    Thank you for you blog, Always a pleasure when I am challlenged to think (again) about aspects of the work I love to do !


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